I would submit that it was not their status as Senators which defeated Dole and Kerry. Even Kerry who was utterly vulnerable on his Senate record, did not suffer as much as he should have because he was attached to a liberal Senate record. He was attacked for his statements and one vote on $87B.
So far, all I have heard against Frist is that he is not dynamic enough and he is vulnerable merely because he is a Senator. I think the former means he has gravitas and the latter is not disqualfying unless he has exposed himself as extremist, which he clearly has not done.
Frist remains the obvious front runner.
By the way, what are Frist's accomplishments?
Finally, ignoring the TradeSports list, if I could choose whoever I wanted, it'd be Cheney. I've been privileged to be able to successfully vote for Cheney four times now--twice as my Congressman and twice as my Vice President. I'd gladly vote for him another two times to be my President. He's my number one pick of famous person with whom I'd like to fly fish.