a couple of years ago when i didn't want to believe that lance was doping i did a little research on the tour podium. this is what i came up with:
out of the 8 other podium finishers from the armstrong era, 6 of them (from what i could find quickly) have been caught out as dopers.
1999: Zulle, doper. Escartin, ???. armstrong winning margin 7+ minutes.
2000: Ulrich, doper. Beloki, doper. armstrong winning maargin 6+ minutes
2001: same podium. armstrong winning margin, 6+ minutes.
2002: Beloki, see bove. Rumsas, doper. armstrong winning margin 7+ minutes.
2003: Ulrich, see above. Vino, doper. winning margin minute.
2004: Kloden, ???. Baso, doper. margin 6+ minutes.
2005: basso, see above. ulrich, see above. winning margin 4+ minutes
of course, there is no way of knowing if these riders were doping during these specific tours, but that is a lot of circumstantial evidence. That he could be so much better than proven dopers is very hard for me to believe.
more interesting circumstantial evidence would be to look at the number of armstrong lieutenants who have since been caught out as dopers.