You know after reading this thread, I think he can go a lot further with a confession that I thought possible this morning.
As has been said, he just spouts about how he was a cyclist, it was his dream so yes he had to dope, but then he became a symbol to millions, and all his bad acts were not to preserve his image, or to win his Tours, he did it solely because he knew they needed hope, just like he did in his darkest hour.
I think given how convincing he has been in interviews saying he didn't cheat for so many years that he could pull that off, and I think it sells.
Obviously those who look closely like the clinic will never buy it as truthful, but I think the average joe on the street will lap it up, because people want to believe. Its the same reason he's lasted this long already.
I also think that the timing couldn't be better. Forgetting the legal consequences (SCA etc), this apology would not have meant as much before now, but now that he is being dropped by everyone, it will be that much more powerful.
Given that he's got no chance against SCA and the Times, he might as well go for it while he's still got the attention of the press.