Originally Posted by nat_ster
Metal frames covered with fabric. The fabric absorbs the noise.
If you have the skills and the tools, one inch square tubing is cheap framing material and takes up less room then a 2X4. Every inch counts if you are building a short schoolie or van. MIG welders are relatively cheap and its pretty easy to learn to weld with one. Once you have the welder ... you can do many projects you couldn't do otherwise.
I bought all the steel I'm going to need (about 100 feet) for the bathroom, dinette, storage racks and (kitchen) counters for about $60.00
Instead of wallboard or plywood wall covering, I'm using plastic sheets. Home Depot has a couple different thicknesses.: woodhttp://www.homedepot.com/p/PLASTEX-1-16-in-x-4-ft-x-8-ft-Plastic-Panel-63003/202090190
If you need insulation, it shouldn't be too hard to find foam one inch thick.
For the "crafty", covering the plastic shouldn't be too hard.