Spontaneously I thought of Tony Freeman too. But he seems like the kind of guy who never quits. A guy that has a youth-type personality, and he also seems to accept his place in the bb world. You know, that he can only get so good placings in a big show and is content with it. I'm guessing he will go on a few years more.
Dexter too. Seems to like the paycheck he gets. He places continously well, never screws up much.
Someone who might, and should, retire is Branch Warren. He is young in bb terms but he has melted away already. So if the judges give him a signal by putting him out of top 6/top 7 he might take the hint.