I like the idea, especially the time allotted for learning GT5. I can assure you that GT5 is a completely different beast from Prologue and vastly different from the GT Academy Beta release.
You're going to need the time.
How are you going to work around time zones? So far you have possible entries from the US, Sweden, Aus and (perhaps UK)
Admin nightmare.
Another idea to mull over (given GT5s screen capture, youtube uploading and possible ghost sharing) would be to decide on a track, decide on a car (including upgrades etc), tyre types etc......and then let everyone post their fastest race times racing against the AI. That's assuming that getting everyone together for an online 16 player race proves difficult. *Ahem, requires honor system*
....and OMG 10GBs install
largest console install in history by at least 4/5gb. At least I have the signature goodies to keep me busy while that's installing.