Are you talking about Aluminum?
The other thing to think about is the (cheapest possible) wood was put in there in 1995, its now 2012 so that is 17 years. Mine is from the 80's so my wood has survived 25+ years. Do you think you'll keep this camper for another 15-25 years? and if you use a decent joining rather than big staples that allow too much flex and wear their holes out and put some care into it you can probably get more use out of wood.
I redid my roof frame with cedar, its light weight and rot resistant so if a little bit of water does get it it won't hurt. Screws tend to strip out easily so I used bolts and t nuts and the bolted together sections allow some bending and flexing.
I'm using plain old homedepot pine for the frame, light and strong. I'm joining with dowels and good waterproof wood glue. The doweled joints you can research and I've tried before to break one and the wood will break elsewhere besides the joint, modern glue is stronger than wood.
If you really wanted to make it good you could prime all the frame with a water resistant paint.
I'm also using plywood rather than paneling so the plywood gives more strength (glued on). Paneling is like gluing to the page of a book, rip that one page out and its done, plywood is like gluing all the book pages together first then gluing to that.
I figure mine will outlast the original.
Wood isn't that bad of a material, most of the rv industry is more a poor construction issue than the fault of wood.
and yes, the lifting mechanism sucks, I cranked mine up quick in the garage one time and didn't notice I didn't have it centered and the roof corner hit the garage door track and stripped the gear. next summer my wife tried to lower with the vanity lid open and stripped it. so I've bought two $35 cranks.