Darkhorse candidate for 2008?

Many conservative are less than thrilled with the names (Giuliani, McCain, etc) being bandied about as potential presidential candidates for 2008. I've maintained that to be successful a candidate does not want to known as a candidate prior to the 2006 mid-terms. Doug Petch is speculating that there is a viable candidate who isn't even in politics anymore. He is touting the idea of Fred Thompson who is currently playing the DA on the TV show Law and Order as a potential darkhorse candidate. Professor Bainbridge has links to Thompson's senate voting record. One thing which surprised me from his bio was his date of birth. For some reason I assumed Fred was older than he is (63). He is 6 years younger than John McCain who is rumored to be interested in running again.