The good news is that The Missing Sync version 2.5 with Treo 700w support on Mac OS X has been released.

The bad news is that it mostly doesn't work. At least not for me. The only feature I could get to work is mounting the device as a disk drive via USB. Syncing via USB doesn't work, and Bluetooth connectivity doesn't work either. I have support requests in to Mark/Space on these issues.