There are some new clues that Mac OS X Leopard will drop G3 support. Its ReadMe file does not mention it, its web pages do not mention it and Apple even made a deliberate change to their 64bit webpage to remove the G3 mention recently. My take: This was not unexpected. For each new version Apple required one more additional feature in order to work (in the past it has been USB, then firewire etc) and now it’s G4+. I bet that the client version of OSX after Leopard would require a supported 3D QuartzExtreme-compliant graphics card in order to boot up.