I don't know where you live and what the availability of these might be, but you might also look into equestrian bras. They have to be comfortable because you don't want to be riding with straps biting your arms off, and I believe that at least some of them are front-fastening. I used to wear an athletic bra that was no actually a riding bra but was very similar and it was very comfortable since it had wide straps and soft material, but held things in place.

I don't mind bras, myself, as long as they're the soft, lace-less, adjustable kind. I've learned that you can't play the guitar with underwires unless you want to hurt yourself.