Posting to say this thread has been a great resource and to say thanks to everyone who posted their designs. Special thanks to all the pros coming here to share their technical knowledge.
I wanted to share my design as well, as I haven't seen anyone doing it exactly this way. My main constraint was cost. I was able to put these together for about 25 bucks a piece. I wanted them to be a little more rugged, so I can move them around for location recording without damaging them. That's why I put the wood on the outside of the fabric. I was kind of wondering if anyone thinks this will have a detrimental effect on their absorption properties. I'm kind of committed to the design at this point anyway I guess.
The wood is 1x2 fir from Home Depot. It's garbage wood, but if you spend a little time sorting it, you can find some straight pieces. It's only 80 cents for 8 feet. I would have preferred to buy from a local lumberyard, but the guy at the pro desk was very helpful in helping me track down the OC 703, so I felt better about it.
The fabric is 1.50 a yard unbleached muslin from Jo-Ann fabric.
OC 703 from a local supplier.