Indurain's Lungs
Legend of Garry Nelson
It's easy to read too much into climbing speed over different climbs in different situations though. One of Armstrong's Alp d'Huez rides was an ITT, where bunch racing is against the others on the road, not the clock. This is certainly not a defence of any of the named riders, just a warning about the nature of statisics!
Yes, the statistics are very unreliable, however as the riders' power outputs aren't published this is about all we've got.
Vaughters did publish some data about climbers 10 years ago putting out 6.8w/kg for around 30 minutes on these climbs whereas Brad was at around 6w/kg yesterday. @Scienceofsport is an interesting twitter if you're into the numbers.