Actually, yes I have.
Let's see . . . 1988, who were the frontrunners? George Bush, Bob Dole and Pat Robertson? Bush, the winner, was not the most conservative of that bunch.
Fast forward to 1996. Frontrunners? Bob Dole, Steve Forbes, Pat Buchanan, and Phil Gramm. Dole was clearly not the most conservative of that bunch either.
2000? Well, George W. Bush was essentially pre-selected. However, he still was not the most conservative in the race either.
Historically, strong conservatives don't fare well in Republican primaries. Ronald Reagan is one of the few exceptions.
Additionally, I am very involved with the Republican Party and speak with some of the key players in Kentucky's Republican Party on a frequent basis. There are many of them who were STRONG George W. Bush supporters in 2000 (and they still are as well) who are saying that they think John McCain is our best bet in '08. Personally, I disagree, but I am not discounting his ability to win the primary.