I think this would be a good feature to change discs from the couch with a media center when you do not want to get up and can't use a memcard.
I'm using a cd plug-in (based on cdrMooby2) which does not support changing the disc while the emulator is running and
while playing the PAL version of Koudelka [SLES-02897] at the end of the first disc I could not save and load from the memcard on the second disc (this is the first game where I had this problem),
so I had to play around for a bit and found a way to get the new disc loaded with a save state.
For this I made a save state at the "Insert next disc" prompt and renamed it so it would load with the next disc and then made a change disc (CD-ROM) and the game continued.
(I was using ePSXe but that shouldn't matter)
So I would like a save state which can be loaded from every game just by pressing a key and then tell the game that the disc has changed after loading (maybe even load automatically after the emulator was started and then delete it).