Ok should we give these a go.. haven't done any of them yet, not sure if anyone else has?
Colle di Sampeyre
Colle dell'Agnello
Colle della Lombarda
Colle della Fauniera
Col du Glandon
I haven't tried it myself yet, but this is the the route for the world time trial championships qualifying, which I will be attending next week. It should be a course where plain power is more important than Watt/kg.
You will need to complete it in something like 37 min. and 30 sec. to qualify if you're < 50 years old.
If you're unlucky to be in my age group (50-54 years), you will probably need to do it a minute faster.
http://www.bkool.com/profile/detail/387630?durationType=DISTANCE&lapCount=1