saw a cooker  made from an old 9kg gas bottle, legs bought it up to a comfortable level laying on its side and a oblong hole cut in the side to hold a grill, (looked like reo) the valve had been removed and a door for the firewood  and the other end had a 2inch chimney
all compenents fitted in the bottle itself, so space required was miniscule 

The Maker had a display at the Perth C&C show complete with a range of accessories.
There are several plans etc. for DIY versions floating around various C&C and 4WD sites.

on a previous thread I told about a OzPig

http://www.ozpig.com.au/sites/default/files/images/pic5.thumbnail.jpg


more info

http://www.ozpig.com.au/

Dave