Check out this product:

It can controll most audio/video components. While it wont help in ripping disks it will allow you to build a custom interface to controll the changer from your mac. Add a firewire or PCI video capture bridge and you can watch movies and rip the DVDs on your mac, all without altering the DVD jukebox in any way.
PB G4 15" 1.2ghz - Pismo G3 400 mhz - iBook G3 500 "Jukebox"
"SawSmurf" G4 500 - Quicksilver G4 Dual 1ghz modding...