Well, here's something to consider.
A guy I met while riding pick-up sprints has a beautiful Circle A track bike. He kicked our butts riding that thing. But, last sprint I went to, he had a pedal strike (struck pedal?) after a race was over. skidded on his side into a small ridge of parking lot concrete. The paint wasn't scratched much (unbelievably) but there was a dent in the top tube.
I can't imagine when the expense of a custom frame is going to be worth the worrying about the inevitable scratch, bump, or wreck. he was a trooper about it, cheerful even (considering how he ate it). I'd be moping and whining for weeks.