I recently got a tip from a friend who is a dealer in heavy gym machinery. He showed me this site:
http://www.uship.com/find . Kind of like a Craigslist of shipping. It's private people and professional truckers who post here to take on extra stuff on trips already planned. I've never personally used anyone from it, so caveat emptor. But my friend swears by it, and hasn't had any losses or problems.
Charles