Question about materials.

Hey folks, i'm a painter moving into a slightly sculptural space, and im looking for the most cost effective and user friendly materials (not always two things that go hand in hand I know) for the job. Heck, even if its expensive id like to be made aware of it. Ill be making wood panels as small as 12"x9" and as big as 8' on a single side with various shapes fixed onto them. I can make the panels, but im still learning the various way to make shapes. Here is an album of some concept work ive been doing to give a better idea of what im going for and what I already know how to do.

http://imgur.com/a/mSN9H

That first image in the album - the piece on the right - the bottom portion has craft board (a kind of cardboard that you wet and bend and let dry into place) with fabric (the camo) glued to it. It worked well enough to do some exploring, but id prefer something that is a little more solid, or perhaps something that could be primed and painted. The 2nd image is two resin pieces that came from the same mold (using oomoo). However, I manipulated the mold within its 2.5 minute work time to alter their shape. The 3rd image has sheets of acrylic that i picked up from home depot that I manipulated with a heat gun.

My first thought was the thousands of different plastics out there. They're usually liter than wood, and difficult to break. Now, im aware of CNC routers and laser cuters - those could be useful for cutting holes or detailing shapes, but what is a material/machine/hand method that I could use that would manipulate the depth in different places? Say, to make waves on the surface. I then looked into bending/warping plywood. I kind of like this idea. I like how solid it would be, but it seems pretty labor intensive and could get rather expensive to do on a large scale. Also, I dont necessarily need nice wood grains as it would often be painted over. I also stumbled upon channel letter bending on youtube. It seems like these folks are using thin acrylic sheets (i guess?) and a heating element or a peg system to bend aluminum.

Another thought was to go with the "found object" method. This would be good for the environment, and my wallet/time. However, im having trouble finding places where "raw" plastics are disposed of. Ive found one dumpster outside of a printing company that I can get those sheets political signs are made out of, but thats about it.

Does anybody have any ideas that I may have missed along the way?