School bus jumps and backwards races are a cool idea, but not needed for good entertainment. About three years back, Miata was the featured marque at the Mitty and somebody had the bright idea to invite Spec Miatas to participate. About a dozen of us showed up. We were repeatedly admonished to comply with the vintage racing no-contact rules and we all nodded in unison, solemnly swearing not to hit the vintage cars. It was not openly discussed, but all the SM guys assumed it was open season between the SM's, as long as no collateral damage was incurred by the vintage guys. We proceeded to race each other hard and trade paint in the usual way, using vintage Vettes and Mustangs as picks. They would blow by us on the back straight, then we would swarm them like angry bees in the twisties. Crazy fun. At least for us.
As far as I know, the dents and scuffs were confined to the SM class, and there was no collateral damage, although I did once "help" a 914-6 up the hill out of Turn 5 (huh?). Incidental. Besides, he needed it. Where's the gratitude?
The Mitty draws quite a crowd, and all of us SM drivers received a jubilant standing-O on the cool-down lap from spectators all the way around the track. They enjoyed watching some real, earnest racing, rather than the usual parade of show cars. The organizers and some of the vintage participants were less amused. Oh, well. It was fun while it lasted.
For what it's worth, I think the inverted field is a good idea. Base it on qualifying times. Using race finishing order introduces too many vagaries. Qualifying is a better indicator of inherent speed. Race in legal SM trim. Be as creative as you want with the prizes past the top three.