I Made my ears out of Leather, and rabbit fur, and my tail is long generic white fur. Both are hand dyed. You can buy purple fur from ebay or your local store I'd imagine? You could also do the shape out of foam, but i found leather got the shape a bit better = ) Good luck with it!
A tutorial would be really helpful. We already have all the fur and fabric we need, just can't seem to size/shape them quite right. ; ; (I love your whole cosplay, by the way....not just the ears. The tooling on the leather is amazing. O.O )