Terry,Stan et al,

 I vaguely remember the story of a '70s bus that after it outlived
 it usefulness on the road was converted for a time to a chicken
 coop on a farm.
 But it's life as a useful entity didn't end there...

 At some stage,presumably after a larger chicken coop was built,
 the owners decided to upgrade their sewerage facilities (or
 presumably the lack of them...) by digging a large hole and
 proceeding to lower the poor old bus in.
 They cut a circular hole in the roof,connected it via a pipe
 to a toilet above and had working septic system!

 Read it in a VW mag some years back...(so it has to be true ;)

 Cheers,
 Steve O