My experience with a combination of G4 and 7600 is that  dual port PCI->USB 
card ( $35) and a dual port SCSI card ( for the G4 @ 99) gives me all the 
cross functional use I could ever anticipate.  I have both machines tied with 
a local ethernet.  My SCSI devices all work on the G4 and all USB devices 
work on the 7600.
The Wiz