Interesting thread. BTW, at least some of these ideas are being done at some level.
Traxxas promotes as Monster Truck events with their own truck. Haven't seen their truck in person, but an event I went to several years ago had RCs blasting around the place between the trucks and the motocrossers that were also part of the show. Surely at events with their truck they have their RC stuff running around somewhere.
Rc Driver does races at Daytona and I think the Brickyard with Nascar rookies. Then they auction the cars for charity. Perhaps they should give a few away to the crowd somehow?