Just prior to the Landis positive, Hein Verdruggem, Armstrong, and a few investors were in talks with the Amaury organization to buy the Tour de France. Problem was, the price was too high. What they needed was a way to lower the price - and the lower the better, no doubt. The possibility that Hein and Armstrong sabotaged Landis for this purpose was first brought to light here in the Clinic. Landis, for his part, eventually confessed all, but has always insisted he wasn't guilty of that particular infraction.
When you couple the financial angle with the fact that no one, to my knowledge, ever left USPS to lead a competing team without subsequently testing positive; and then add in that such a scheme would be in keeping with armstrong's personality -- you have a scenario where all the pieces fit. Highly likely, even. I wouldn't be surprised if Landis agrees.
(And you know, had they bought it, we'd have heard it called "Tour de Lance" forevermore.)
Edit: But to bring it back on topic, clean cycling is for me is as pornography famously was for U.S. Supreme Court Justice Potter Stewart: I can't define it, but I know it when I see it. I don't need to know that the riders are "clean" down to the Nth degree. I don't think such a standard is practical. I just need to know that they are racing as human beings, not extraterrestrials, that they are suffering and giving their all, that none has an undue advantage. They prove they are clean simply by being clean. People with eyes usually can see the difference, and if you can't then it doesn't matter as much.
(And by the way, it's all well and good to say the peloton today is cleaner than ever, but if that simply means that only a few riders are permitted to go overboard while everyone else is held back, as it is today with Sky, well, then racing as a whole is dirtier than ever.)