love this question! i'd make an IROC for downhill (at least what i remember IROC (international race of champions) from the 80's being...maybe it still exists?). X number of venues with X number of pre-selected racers run the same bike, suspension and tire manufacturer. each venue bike, suspension and tires change. brakes, cockpit and drivetrain can be whatever they want the series has no UCI affiliation. example - val di sole, everyone is on specialized, ohlins and maxxis - les gets, commencal, fox and schwalbe - MSA trek, rockshox and continental - last race of the season is riders choosing...