i dont know much about canvas tents.mine have always been nylon.

all i know is this...i love the tents i have.i have a 2 person u.s.m.c tent made by eureka and i love it.i paid 250 for it new on e-bay and i recently saw them used for 99 bucks at "cheaper then dirt".its heavy as hell but thats because its so heavy duty.its what the marines where living in in iraq,sometimes for 6-12 months at a time.completely waterproof.i put a 60 lumen surefire rite up to the rain fly at night from the inside and it wasnt at all visible from the other side.
the marines wanted it that way so that they could use lights in the tents and not give away their possitions.

the other tent i have is a catoma 1 man combat bivy.great design and handy as hell.its what i use 90% of the time.i have slept in absolute pouring rain all night long and didnt have the slightest problem.i love that thing.i got that on e-bay also.one of the best investments i've made as far as outdoor gear goes.

snugpak is making a 1 man bivy that is 100 bucks brand new and it looks very lite.i will have to check that out.

northface now makes the army's extreme cold weather tent which looks like a wet dream to me exept its 600 used.the army's paying a few grand a piece brand new.

i realize that these mite not be what your looking for but figured that it mite help someone.just my experiences,thanks