I use cotogps running on Palm TX and Holux GPSlim BT to record tracks from MTB rides.
Cotogps has a GPX export facility, but it produces GPX that is not conformant with either GPX 1.0 or GPX 1.1. I wrote some XSLT that converts cotogps GPX output to GPX 1.1 and will be happy to send it to anyone who wants it or will post it here (is that OK, moderator?).
