I was ever spawned in a room like this (I am posting a manually made screenshot, because I didn't think of making one when I was playing):
####+#####
#ssssssss#
#s......s#
#s...@..s#
#ssssssss#
##########
It was not EXACTLY that neat (about 2 or 3 lost souls were missing) but it's just kinda to give you the idea.
BTW, sorry for topic necromancy =P