I know what you mean, I've only missed one year at RA in the last six or seven. I was there a few years ago when they had something like 70 Can Am cars on the track at the same time. The sound of them coming down to Canada Corner was unreal. Unfortunately the Can Am fields the last few years seem to be thinning. Fran, I don't know if you made it to the BRIC last month but I think there were only two or three Can Am cars competing on Sunday. They didn't have a dedicated Can Am race this year, which probably had something to do with it.
At any rate, the best vintage Can Am race I've seen was at Monterey in '98, when two 917/30s went head-to-head with a Shadow and one or two other cars. The lead changed every lap for several laps, and the drivers were really going for it--I saw several daredevil passing moves involving locked brakes and barely-missed bodywork. It was really stirring stuff, possibly better than a lot of the "real" racing in the era of utter McLaren/Porsche domination--
Bob