Give me a couple minutes...
Alright, really quick notes:
1. PowerBook G4 12", 867 MHz (officially supported by Leopard,) running 10.2.8. LeopardAssist has 'generic' icon. Loads, but cannot click "Continue" with the mouse. Using "enter" on the keyboard moves to next screen fine. But it means I must accept all defaults. And it means I can't go back at any point. Properly sets boot to optical drive just fine, boots optical drive in Normal Startup mode. Leopard installer seems to work fine. (Not taking the time to do a full install.)
2. iMac G4 18", 800 MHz (the last OS 9 bootable model, NOT officially supported by Leopard,) running 10.2.8. Same behavior inside the LeopardAssist interface: must use keyboard, can't click anything. Also does *NOT* appear to set the speed properly, as the Leopard install disc gives me the "Mac OS X cannot be installed on this computer." error. LeopardAssist works exactly as expected on the same system from 10.3.9, setting the CPU speed properly for the Leopard disc to be willing to install. (I did not take the time to actually install.)