Comment by jseal for Here's a Poor man lidar, that could be used for mapping. It uses a sharp IR sensor and a servo.http://www.pirobot.org/blog/0014/The xv-11 laser is a fairly cheap setup for under $100 on eBay. http://wiki.ros.org/xv_11_laser_driver

I like the idea, I'll have to follow up with you to see how well it works out. You could use a couple of bumpers in the front to protect against blind spots.