Have you considered Blur Sliver ? it has awesome synergy with both the gemhide and manaweft

Gaffa Funny that you mentioned that. I actually changed the deck about a month ago and cut a Clifftop Retreat and the Bonescythe Sliver to play two of the Blur Sliver . the haste does much more for this deck that the double strike, especially when the main goal is to slam Door to Nothingness .

Thank you for the reminder, I just changed it to the current deck list!

or even Heart Sliver he's even cheaper than blur sliver

Akhos I like running Blur Sliver over Heart Sliver because of the 2/2 body. Costing three as apposed to two doesn't hurt my curve very much and I would much rather drop a Predatory Sliver , Sinew Sliver , or Sentinel Sliver turn 2.

i would probably say Firewake Sliver over Blur Sliver as it will give you an alternative win-con, while still providing you haste, and it would be just as easy to cast as you should always have green, and would only need the same red.

Also, Cavern of Souls would be a good add, to stop your slivers being countered by control decks.

Also just had a brain-wave.... Mycosynth Lattice ... Everything is are artifacts, so you can blow up their lands easier, everything can be cast regaurdless of colour! AND makes all of you're mana anymana for the Door to Nothingness !!

Why don't you try Sliver Hive.