@olegil
But UAE-JIT does have custom chipset emulation.
However, to answer your question regarding what use there would be for another JIT emulation, that depends on how good Trance and Petunia turn out to be in practice, doesn't it? Bernie's JIT work has a proven pedigree, which is more than can be said for the other two at this moment in time.
Bernie always said he would have a bash at producing a PPC version of his JIT emulation if someone provided him with a PPC system to work on. It seems that once again he has delivered on his promises.