I came up with this build, but I fear that the Assassins AL means that he would take too much damage, but anywhere here it is. If anyone could test this out for me, it would be appreciated.
Skills :
(Sorry I dont know how to use the new icons, hope someone can do it for me)
-Sympathetic Visage (to stop the grasps interrupting + the smites healing )
-Ancestors Visage (used after SV - so that a visage will be up at all times)
-Lead Attack (in build theory, this was 'Golden Fox Strike' because SV is an enchant)
-Offhand Attack (in theory this was 'Golden Phoenix Strike')
-Dual Attack (Death Blossom for some nice multiple target damage)
-Flashing Blades (E) - 75% chance to block incoming attacks while attacking. With this up all of the time, you shouldnt get hit much.
-Shadow Refuge - Can be used WITH Flashing Blades, thats why I didnt take Feigned Neutrality.
-Dark Escape - For the run to the smites.
Attrib : Dagger Mastery = 12+1+3
Rest should go in Illusion and Shadow Arts, and remainders in Critical Strikes. Wiki is playing up, so i cant check the attrib balance.
Armor : Not too sure. Maybe the +15AL while attacking would be a good idea. (Nightstalkers).
Weapon : Zealous STANCED Daggers of Shelter (Yes im buffing the AL

I hope most people know the concept behind a smite run with SV and AV, but anyway :
1) Enter UW
2) Take the quest 'Clearing the Chamber' from the ghost.
3) Put up a visage before aggroing a group (3/4/5) of grasps, then use dark escape to pull them to a safe location.
4) Maintain Flashing Blades.
5) Let out your combo.
6) Use Shadow Refuge as a heal.
7) Repeat until the 3 groups around the chamber are clear.
8) Run to the smites.... i cant find the video atm, but i know Witte posted one somewhere.
9) SMITES! Ecto time.
10) Remember to keep SV/AV up at all times, and do not attack a smite that is using SoJ.
11) Keep Flashing Blades up as well, heal when needed.
12) The first part of the fight with a group of smites will be the hardest because of Zealots Fire, so make sure you heal.
13) Rinse and repeat for other groups. GL on ectos.
EDIT : Watch out for the enchant stripping nightmares.
Typically I deleted my SSin 2 weeks ago.... so I cant test this build. if anyone could do it for me, it would be appreciated (get some SS's).
If anyone generally has a problem with the build, or thinks that there is something I have missed out, either reply to this thread or PM me.
Cheers, hope it works

Anyone familar with the other grasps + smite runs should be able to use this build correctly, however like I said the AL could be a problem.
Suggestions appreciated, flame posts like 'OMG SSIN CANNOT SOLO UW' are not appreciated.
Credit to myself, even if attack skills are changed

*hopes it works*