Before the flames, this is a FUN build, not a competitive build.
I use my standard AD build for this:
I usually call bot lane.
Fun part, Items:
2 HP Pots
Brutalizer -> Ghostblade
Cutlass -> Gunblade
The items I chose were ALL based around Death Mark. which deals physical damage, so the runes and masteries I have were intended on boosting it's effectiveness. Let's look at it in detail.
ACTIVE: Zed becomes untargetable and dashes to target enemy champion. Upon arrival, he marks the target for death and spawns a living shadow behind the target. This shadow lasts 4 seconds and mimics Zed's abilities. Reactivating Death Mark will cause Zed to switch positions with this shadow.
After 3 seconds, the mark will detonate, dealing physical damage equal to 100% of Zed's attack damage plus a percentage of all magic and physical damage dealt to the target by Zed and his shadows while the mark was active. (BONUS PHYSICAL DAMAGE: 20 / 35 / 50% of damage dealt)
So physical AND magic damage are calculated into the bonus. But wait... Zed doesn't do magic damge! Oh wait, yes he does! With activated or passives from items! So some quick math, since I'm REALLY not good at math and willing to admit it.
DFG: Active: Deals magic damage to target champion equal to 15% of their current Health (+5% per 100 Ability Power) with a minimum of 200 damage (60 second cooldown).
Gunblade: Active: Deals 300 magic damage and slows the target champion's Movement Speed by 50% for 3 seconds (60 second cooldown).
Let's assume that Zed has 180 AP from items. As a target dummy, our enemy has 3000 health and 100 Armor and MR.
Opening with Ghostblade active and Deathmark. Immediately applying DFG, 225 dmg and Gunblade, 150 dmg. A fully charged Odyn's Veil adds another 100 dmg. A Physical bonus of 187 after resists and armor. A total of 662 Damage, NOT INCLUDING his basic attacks and spells or the base damage of the ultimate. That's just bonus damage. Reason I'm not calculating his basic spells in (besides the fact that I suck at math) is that there are too many other variables to account for. Whether or not you had the energy/CD for Living Shadow before the combo, whether all of your skillshots and shadow skillshots landed and if you chose to get Sunfire Cape, or if they beat themselves up on your Thornmail... IF you land them all within 3 seconds this adds up to +1000s dmg. It's doable, I landed them fairly easily. Also, with all the CDR from the items I chose, the Ulti CD is very close to the same as the item CDs
Now, if this shoddy math doesn't entice you enough to try it for yourself then just take my word for it. I tried it once, it worked, and it was fun. It helped counter vs an Irelia that was rocking Ninja Tabi and Randuin's Omen against me Bot lane 1v1. One item I want to try next time would be Blackfire Torch with this build. Most summoner's won't be prepared for Active Ability Zed.