There *are* ways to put multiple games onto a DVD. The tutorial I read, however, said that the success rate using PSX games is rather low, and I was just wondering if I could put multiple discs for the same game on the DVD, and when the game prompts me for a disc change, it would allow me to switch to the other disk.
http://www.home.zonnet.nl/joeriroels..._DVD_-JRLS.htm
This is a guide which explains how you can put multiple games on a single DVD... it just doesn't say whether or not multi-cd PSX games are working.
UPDATE: It also does not mention putting PSX games onto DVD at all... logically speaking, shouldn't this work the same way as a CD-based PS2 game?