so at this point whats your options

1) internal drive + controller card

2) firewire drive, which is proving hard to find without a ridiculous price

3) usb2.0 drive + controller card

4) scsi (good luck)

I guess its up to your budget and which option you like better?

edit:

actually scsi is not that horrible of an option, most drives seem to be under 100$, which is retarded for a dvd rom (no write) but by the time you add in all the cost's of the above options (cards cables boxes ect) it might be the cheaper option