Ace. I can't help too much on the helping organise, but i'll help in anyway possible if its possible. Money is the bigggg thing. Working out fuel, petrol stations, places to stay, charges for tolls, charges for the tunnel, breakdown in emergency (with enough of us someone hopefully is technical enough). Sooo many things, but theres plenty of time to work it all out.
As for numbers, don't worry to much about waiting for enough people to join it and say "yeah, i'll go". As 8/10 will say that and then not go, thus why these things fail. To be fair, it just needs to be put up and let the organisation over the coming months swindle people into joining up, and helping. Its one of those things its only going to succeed if it snowballs over the coming months, follow?
Theres enough dedicated GP owners out there to give this a go. Even 3 cars is great, be fun to see how many actually do this. Photo's of our GP's in the Alps, in Italy....once in a lifetime. So So So So So going to be worth it!
Also, doubling up and doing the Punto International meet in 2014, in Italy. Just wow.