*Results*
Basicly after running a dozen or so bot matches and close to the same solo que matches, frankly Nasus does a better job in every way possible but for his /dance. Nasus will do more DPS, better AoE, better lane control, near the same health, targetable snare for escape and chase, and his ult doesn't bug 9 times out of 10.

**Recent stuff up here***
Bot matches (lol) are going well with the build, able to tower dive with great ease, take on wave after wave of creep without losing HP, soak up damage, so on so on.

Build order thus far:
Vamp Scepter (Early game survivability mixed with War's natural lifesteal)
Emblem of Valor (More lifesteal, health regen for your lane partner)
--OR Executioner's Call for the heal debuff, depends on enemy team makeup)
Boots of Speed -> Berserker Boots (Attack speed is important for the lifesteal)
Cloth Armor -> Madred's Razor (Kill lane creep faster, proc = high health steal, armor)
Chain Armor -> Atma's Impaler (More armor, War's natural HP adds to your DPS)
Warmogs/Force of Nature (Melee heavy team gets the first, magic heavy gets the second)
Madred's Razor upgrades to Blood Razor for late game tank nomming

This will no doubt be shuffled around and changed, but what I'm testing for now.

Summoner Spells: Cleanse and Flash. Originally thought of Cleanse and Ghost, but flash allows warps through trees and cliffs, rather nice.

Runes:
Marks - Attack Speed
Seals - Health/Level
Glyphs - MP/5 (Takes some reliance off of golem)
Quints - Attack Speed

Random Thoughts: Possibly taking the Razor first in order to build the same as a Jungling warwick until 6, thus allowing a second lane to be soloed until then, give someone an extra boost until you rejoin for more official tankidge work.

***Original Post***
Let me start out by saying I know Warwick will not be the ideal tank, and yes others do the job better, I know. However I really like the character, he has the POTENTIAL to fill the roll, and there are more carries than you can shake a stick at now adays compaired to tanks in PUBs. This is just a curious attempt at experimentation.

So, as a ganker Warick is going down the totem pole rather quickly.. His ult can be countered in more ways than I care to list, so on so on, pretty much everyone knows his state ATM. While that method of play is quite nice in premades, in pubs it's rather lackluster. While I do hope he'll be getting a patch, I was playing Nasus as a tanky sort of fellow, and thought about Warwick doing the same. Base healthpool wise he's nothing to sneeze at, and with HP items he can rival most of the normal tanks. What Warwick does have going for him is health steal + attack speed. While that can be easily shut down with stuns ect, cleanse, snare reducers, and his speed buff can at times counter it.

Basic idea was going to be zerker/Merc boots depending on how much CC they have, executioner's call for 18% life steal, crit, and heal reduction at a very cheap, easy to get early game price. Frozen mallet gives him a nice chunk of HP, and due to how fast he attacks, will keep them slowed even with the slight nerf coming to it. Alternative or addition to Execs is Starks, additional 20% lifesteal, AoE buff, faster attack speed, ect ect. Run speed around weakened heroes is nice if your lane partner gets them just low enough, and with the lifesteal alone (not counting stuns), I've had two groups of creep and an allister wailing on me, and I outhealed it with the occasional hungering strike. Able to towerdive due to how much HP I have, and a HS to nearby creeps can keep me going easy.

End Item build:
Executioner's Calling +/Or Starks Fevor
Berserker's Boots/Merc Boots
Frozen Mallet
Sunfire Cape
Warmog's Armor

From what I've gathered on minimal testing
Pros:
Very high health (Easy 4K+), mixed with very high lifesteal
Good tower push possibilities with speed boost buff
Anti heal + rapid snare
Fun in quick paced fights

Cons:
Weak early game
Bad mana efficiency (May still depend on golem)
Anti heal will cut his survival in half
Only summoner spells for escape
Not the best in the attempted field.
Lack of AoE

Other items I have been looking at include the Tiamat (health regen, mana regen, splash damage for creep pushing, more damage = more lifesteal) or sunfire for bonus health and the AoE. Sunfire would probably be better for base health gain and the armor.

No doubt I'll be editing this post rather frequently, but feel free to add in your thoughts or suggestions. Never know unless you try, after all.

interesting ideas any success in solo ques?

I think the problem with tankish Warwick is that he'd be pretty useless in a team fight. He has his ult which stuns both himself and the other enemy, but they could easily disrupt you while you're in the middle of your ult (same could be said for any other channeling ults). IMO it'd be tough to kill Warwick with this set-up especially with his lifesteal 1v1.

Also, did you test this out in a pub match or a practice match?
I think you should add Madred's Bloodrazor just because it'd help him out a lot in fights.

I havn't done solo ques yet, as I want to iron out as many details as I can before I go ruining people's games by bad play ~.^ Tweaking the item builds here or there and swiching up their priority. I know bot matches are no way to test, but thus far my most 'lawl' moment was me against a set of creeps, Ryze, and the yeti all wailing on me and even with the snowball slow, I was outhealing their damage along with the amount of armor I had negating a lot from the creeps. The biggest success I've had so far is as an assist tank, with being fast + durable, able to keep the frozen mallet proc going and allowing the one in the lane to just go to town on them, and if they get close to the turret, war's ult is an awesome way to hold them for the finishing blow, as more than likely they already used cleanse

No PUBs yet, as I don't want people getting angry until I've figured out a decent path. While he's not the best in team based fights, my experience as a ganker warwick is the team goes "OMG WOLF KILL IT!!!!", now, if you're a hard to kill version of him, their wasting time while the real threats are taking them out, ontop of his ability to finish off runners, or simply catch up to them to slow. I LOVE the blood razor, I'm just trying to figure out how to put it into my build and when, what item it should take priority over, so on.

Interesting one, I might have to try out a tank-Warwick some time. He's so outclassed in the assassin department these days it isn't funny, but I kind of want to like him.

With 4k health, it sounds like it's crying out for Atma's Impaler... more damage, good boost to ult and a definite boost to survivability (more damage = more life stolen). It's not that expensive, either, but I'm not sure where it'd go on the build.

I was also thinking of that as well. More damage combined with Starks + more health gained, so it's a double wammy there, same goes for the blood razor. Thus far with frozen malet, sunfire cloak, and fully fed warmogs Warwick sits at 4473 HP, 130 armor, 58 magic resist (With some runes and masteries included), obviously able to get higher depending on your priority or preference. Mana isn't too bad of an issue late game as your auto attacks do most of the work in this guild. I may drop the sunfire for something else, atma's sounds like a nice alternative, stack that with the razor and that's a lotta lifesteal

EDIT: Dropping the cloak for Atma's, brings my HP to 4023, armor to 130, but my attack is 215, with higher crit. Yum yum lifesteal

It's a good concept though, especially since I'd go for Warwick as well when he's ulting someone on my team. The problem is that Warwick isn't just as much as threat as DPS kings like Yi and Trynd, so they're still the targets to take out in fights.
I agree that he's really good at chasing, but yi and trynd are so much better at running away (unless trynd gets slowed).

I'd suggest stacking MR or armor though, rather than going all out with HP. Imo you will get focused on when you're ulting, so you really need the decreased damage intake. Then you can just pop a HS and run away or something. You could also add a Force of Nature and spec HP regen for the lols. Not sure how that would work out though.

This is true, but sadly I can either go HP, or armor, and lower HP means less lifesteal with the Atma, and it's hard to balance it with the limited slots. The way I'm taking War here is using his ult as little as possible rather than as often, only as a clear finisher or support helper, no more going out on my own. In addition to not being a jungler I can take things like cleanse and flash, that if my ult DOES backfire, I can get out of it.

I tried to play a tankish warwick once and i was quite successfull in a solo queueing game.

My item build was quite simple:

Berserker Greaves (going jungling with only the dagger and a health potion / dont take smite! its gonna ruin your lategame)
Sword of Occult
Leviathan Armor (thats what makes my build tanky)
Black Cleaver (optional)
Warmogs Armor (optional / dont think its necessary)
Atmas Impaler (didnt made it so far)

Of course you need to gank a lot if you are going for the double snowball items. But if you are doing well you gonna have 3,8k HP at level 18 with 20 stacks. plus the damage reduction.
just remember not to die ;D