BTW for the Tour de France it really stands at
VINOKOUROV Alexandre - Favorite to win the Tour, Failed a drug test, he left and His WHOLE TEAM left too (the team hadn't failed the blood tests)
RASMUSSEN Michael - Yellow Jersey - Leading the Tour - left the Tour at his teams insistence. No blood doping has yet been reported (but that is what is probably going on) [Edit:] Actually he got booted from his team because he did not show up for a pre-tour screening and did not account for his whereabouts. He was fined but in his case there is no evidence of doping. (at this point)
And of course there was the debacle last year bunch of riders popped in Operación Puerto
Oh and of course last year's winner Floyd Landis is still slugging it out in court, he has not yet been stripped of his title.