I am a little biased on this one; I own one I picked up a Goodwill sans controller...I have yet to do anything with it, but it seems a capable beast!
Check it out - the MGA Tarantula (linking to an ebay auction with them for sale):
I can't vouch for the seller.
Here are a couple of papers detailing interfacing (and a LIDAR system for terrain mapping/planning):
Once again, I am not affiliated with any of these people; I don't stand to make any money off the auction or whatnot - it was just a source (if I had the money and a place to put them - they are HUGE for an RC car - covering about a 24 inch diameter circle - I would buy all six in a heartbeat).
Like I said, I found one of these - and I just happened upon those papers during some googling on "low cost LIDAR"...
Hmm - I just realized this may have worked better in bar/sport - mods, if you can move it there it would probably be better since this isn't a question, per se.[/edit]