Check out the Velodyne LIDAR sensor - $75k (so the $5k is now "inexpensive")
http://www.velodyne.com/lidar/vision/default.aspx
It was used to create a Radiohead music video - pretty neat site I found recently
http://code.google.com/creative/radiohead/
Make sure you check out the "Explore Data Visualization" link - you can rotate and zoom the point cloud while it is playing 