I was thinking of doing the same thing, which is why I ordered one of the 'ROMY' (which allows 1MB kickstart roms) chips, though I need to get an EEPROM burner to put it into the real Amiga after I test it in WinUAE.
I was thinking of trying to put in the 68060.library or something, I do know probably the easiest way to see what needs to be put in a custom rom is to see what startup-sequence has in the patches file, also probably to include the rom update from 3.9 BB2. That would at least save the reset.
slaapliedje