Very recent article wrt Canseco/Clemens.
“You have to understand this, everyone came to me for steroids and information back then, I was the man, period,” says Canseco. “He never brought it up that he ever wanted to use it, acquire it period. Roger to me was the straightest guy I’ve ever seen in my life, I never saw him cheat on his wife, I never saw him flirt, nothing.”
http://boston.cbslocal.com/2012/05/22/canseco-regrets-juiced-believes-clemens-never-used-steroids/
Of course, as with McNamee, I think you have to be careful with what Canseco says. He may have been right about a lot of things but he's also a bit weasly and will obviously do anything for a buck.
As for the circumstanial evidence, I think you can throw that out there with anyone who played during a 15-20 year timeframe. Should no one from that time make the HOF? Or is there a "NO PRICKS" rule? Only nice guys?