i have yet to hear a poor sounding custom. the only sites i know of are kaiserkalls.com, and lightsout.com. if you go to ushuntingforums.com (if they are still running, i haven't been there forever) they had a forum for custom call makers. quite a few guys on there.
there are more guys on here that make their own. more than i would have guessed. of the ones i've heard, you wouldn't go wrong with any of them