Your sister is very talented. I've never tried to make armor pieces before, I imagine it must be difficult.
I love cosplay, I've not done a WoW cosplay though.
This yes for Halloween I was the Baby Jane splicer from bioshock:

I was a Dalek from Doctor Who the year before- I'll have to dig up a picture from somewhere.
My husband and I always do "themed" dress ups and I make both our costumes. It is a lot of fun. I aways go crazy trying to get it "just right."