I'm going to requote my list earlier in the thread, I think it is a pretty good guide to what is and what is not IB:
I agree 99 %. That 1 % I don't agree on is Transgender. Usually I don't think transgender counts as IB, but I'm thinking about the clip from "Shuukan! Story Land" featured a few weeks ago. The man never actually becomes a woman (I think), but his constant pursuit of greater female beauty makes it qualify.