I am getting harassing myspace messages, now emails, email matches myspace account. I know I can't trace the gmail account but can I figure out who this is through the myspace account? Pretty much a blank account no friends just Tom... what a looser this guy must be... LOL :D

If they provide no information on the account, then there's no way to find out who it is. Perhaps create an alternate account pretending to be someone else, friend him, and find out who it is that way.

Perhaps its an ex? Or their girlfriends?

Well you probably can if you know how to hack... nowadays hacking can do anything... finding where people lives , hacking programs and many things.