Great Pics! 
Here's a image I grabbed off the net. Originally someone called it a "Redneck tornado shelter."
I say it might work pretty good as long as it is not right next to a lake or river or in a flood area. As long as it is secured better so no winds can get in and rip doors off etc. Would have to secure the outside door to the underground and put some chamo over it rocks and etc. and then enter it from inside the house. In case high winds tear the house clear up off the foundations there would have to be some kind of seal so people could go in the bus and not have that entry door to the bus torn off. Maybe some reinforced door fastened securely inside bus...
Notice how the house has a basement and someone has build a concrete thing out connecting to the side of the bus. Looks like they have use of the whole basement and the bus too. More could be done to make it secure and virtually invisible. I would dig down and have food stores buried near the bus with access from inside the bus...
- Yowbarb
http://www.survivalistboards.com/showthread.php?t=171910 Buried School Bus = Storm Shelter
