The 7500 power supply will work in the 7200. I don't have a spare because I have only one, which is what I use to test x500 motherboards.

You can convert an ATX, if you put an inverter on the soft-power-on line. I think instructions are in an article at xlr8yourmac.com. But it might be difficult to find an ATX supply the right shape for the 7200/7500 case.

An 8500/9500 power supply would also work electrically, but won't fit.