Try the 'Bay or some of the shops listed here (SIMS) and chriswoods (don't remember the exact address. You can use am Rg470 as long as it is routed for an Edge or Lo Pro and I think I saw one here in the classifieds. Posting a "WTB" ad looking for bodies in the classifieds is a sure way to get some responses
I think it's a good thing to actually get a beater RG5xx so you have a neck and all the hardware which will be alot cheaper in the end, then you just have it routed the way you want and refinishes and VIOLA! you have your own custom RG/Jem. Good luck.