Exactly. This year Hotchkis is running it's own Autocross series with the NMCA at Fontana,CA and the Carlisle event. For what we are talking about here, I'd rather meet at the show(s) in a car corral, do a 100 mile Road Rally to a track, and have at it for the day, then rally back to the corral.
Classes:
A,B, E Bodies
Modern (LX/ guys)
Viper
Other (Truck, C Body, F,M,J, etc)

The toughest sell is on participation. This would need 6 months of lead time and a LOT of hyping. Event with all that, I would be impressed if we had 20-30 cars. Everyone talks a big game until it's time to throw hats in the ring, then everyone has got an excuse.