Ibanez boards are actually 430mm which is almost 17" radius, but that's not a difficult thing to change.
Anyway, If you want a JEM, for $500 the 555 is a good buy. They play well, the TRS trems aren't as good as an edge, but overall they aren't a horrid trem. The OFR is an option but will likely require a route touch up on the body. You can find a used Lo Pro Edge or standard Edge used sometimes for like $100, then you can pretty easily swap the edge into the 555, just change the studs and stud bushings out.
Buying a Used 570 or something is also an option, but if you want the cosmetic features of the JEM, you'd be further ahead buying the JEM.