heres something to chew on
Boot japanese RR7, go to time trial, select a track, select a car, then when you see "begin time trial", take out the disk and insert a dual-layer dvd with the contents of the bdrom RR7 disk burned to it, then press "begin time trial", the track will load and you can race, exit and generally just play the game as normal (from the backup disk!), might be useful if you have 2 ps3's and one copy of rr7, or if you want to try modifying data on the disk to trick the ps3 into booting said data.
Only problem with this method is the music doesn't work when you're playing off the backup, since the music is saved to the bdrom as an audio track i assume.