Thread
The 6500 isn't really an optimal OS X machine.You could put OS X on it...
Unsupported, but in progress. The main problem is that SCSI and Ethernet are not working, which makes installation difficult. Also, will not work with Mac OS X 10.3 or later, because of 603 CPU.
With only 64MB of RAM, stay with a pre-X OS, of course. Even with lots of RAM, OS X on that machine (upgraded though it is) would likely be a frustrating experience. So, unless you absolutely need OS X to run some precious app, and can also beef up the RAM, stick with 8.something (for example).