Some people probably draft their own pattern. But you might be able to modify a leotard pattern. Kwik Sew has several, and Green Pepper has a few. Some cosplayers put boning in the bodice for more support, so that's another thing to consider. Hope this helps a little!
Edit: there are two bunny suit tutorials on deviantArt. They might give you some ideas on how to draft your own pattern.
Last edited by PSY-chan : 02-28-2013 at 04:45 PM.