Oh oh oh oh, you can get some nice water resistant stuff from civil war suttlery shop... you prolly dont have any near by unless you live by a battle site but you can get em off the net! Great idea man sounds like a fun time!

Anyways http://www.fcsutler.com/fccanvas.asp You could prolly buy that and then perhaps sew them together if need be to make a teepee. I use a tent like that for when i do civil war reenacting and Its pretty nice.



EDIT that might be too expensive for you... um then you can just find some high quality tarp somewhere, if its not water proofed spray some polyurethane on it, i dunno if that would work but mabye