Correction: a 7500 in a really horrible excuse for a tower.
I was under the impression, which is probably wrong, that the 7200 had a lower-rated power supply than the 7500, but I could be completely wrong about that? Other than that I'm pretty sure the form factor is the same across all the 7xxx-8xxx-boards. So far as I know the only meaningful distinction between the 7500 and the 8500 is the lowest-end 7500s came with a PPC601 CPU card, while the 8500 was never sold with anything less than a 604.
The 9xxx's of course have the six slot board, so that won't fit.