I had the cartridge that inserted into the back of the ps1 and had the spring that kept the disk spinning so once the system booted, you could swap out and play burned games and imports as well.
I think it even had a hex editor to enter codes
remember playing all the import dbz games before they even made games for Americans
I think a friend of mine had something like that but not with the spring. You'd have to let the demo gain momentum, then swap it with the burned game.