I have an idea how to run PS3 backups. Here is what we need:
1) Original game (for example GTA4)
2) PARAM.SFO from GTA4 disc
3) Backup image of game you want to play
4) Bluray burner, BD-R
First we need rebuild backup iso, go to PS3_GAME dir, and replace original PARAM.SFO with gta's one, so now you have backup image with GTA4 PARAM.SFO
Second, burn this new image on BD-R
Third, insert original game in your PS3, disc will recognized, now open your console and swap original with burned backup.
Run the game.
PS3 check PARAM.SFO, recognised it, and game will run.
Its theory of course, DEVs what do you think about this method?
if your backup iso has PARAM.SFO already in the image then its the same as the one on a real disc.. so there would be no point replace PARAM.SFO iso with original disc gta's they both the same arent they?