Here's the one I built. Inspired by The Fisherman Guy.
I've slept three guys in it at once, and it's been great. Not very light though.
With my Big Buddy heater, I can sit in shirt sleeves in -20C weather. The wood stove is nicer in TheFishermanGuy's, but my heater works ok too.
Here's the thread outlining how I built it, with costs, all through the various stages.
http://www.outdoorsmenforum.ca/showthread.php?t=24357
Also this link to another smaller version...
http://home.cogeco.ca/~charrons/Default.htm
