I recently went to my local comic-con (Norcon) as an Eldar Striking Scorpion. My build thread is back on the Mutant / Xenos and heretics page if you wan to check it out.
The Photo below is a good shot of the costume in action (with thanks to the Storm Trooper who posed for the photo!)
I was fairly pleased overall with how it looked. I had a few Warhammer fans come up and ask about it - questions ranged from 'isn't that an imperial chainsword?' to 'How is the Craftworld these days?'.
All in all it was great laugh and I'm definitely doing this again!
WH40K Pepakura File Library 
