Tsk, no takers? Dreadful pity.

Back to the OP:

It seems to me that any chair that could normally handle the weight of a person of substance could be easily modified for essential functions, with the receptacle moved to suit the situation.

I recall images of an extended situation in ??Australia?? where the creative use of lawn chairs and pits for personal business was quite inspiring. Can't find a link offhand, but it's out there.