Bunk Bed Bus

The idea of a bus designed such that you can sleep on it is not new. The key difference here is the design. Three or four rows of single-person bunk beds going down the length of the bus. Instead of seatbelts, the beds would have lids, much like a padded coffin but easier to get out of. The lids would be transparent, so you can lie and watch out the window if you don't feel like sleeping (and to help prevent people making - ahem - messes).

I'm willing to bet you could stack three or four beds, with the lowest one sitting directly on the floor, and the highest being just far enough from the ceiling that you can get in and out.