I was wandering that you could do a tanky dps shen insanely well if your fed.
Build
Warmog's plus Atamas impaler
Merc treads for the tenacity
Trinity Force
I haven't really experimented with my build yet so I really don't know the rest of the build or the runes. (I don't even have enough runes to fill 1 page).
To make this build work at its full potential you need to farm farm farm.With all the split pushing you will be doing because of your ult.

DPS Shen works better with attack speed and on-hit effects like a Kog'maw. His dagger will heal him for crazy amounts, and he'll still be dealing lots of damage (especially with some magic pen). In this case, a Madred's+Frozen Mallet would be a better combo than Atmog's.

But if you're trying to build him like Renekton, it's not going to work. He just doesn't have the skillset. He's a support tank through and through, and any other role will be subpar. :/