I've been to most of these so can get away with just riding the trails I know. We're actuall doing two days in Morzine, using the lift system to ride the PDS area – partly to show a mate, who has guided extensively elsewhere, how their linked lift system works. I've dh'ed my brains out there enough now to worry about abit of wasted double track time ;o)
Interesting about montgenevre, that's one of our experiment places. Will report back and see how I find it.
This mad idea came about after I spend a season travelling around the alps last summer and realised just how close these resorts actually are.