Thanks alot for all the compliments guys, really. I'll have that tutorial done sometime soon (probably around Tues-Wed). Just to give a quick rundown though, I used MDF for the frames. Normally, I would NEVER think to use MDF, especially raw MDF, but after seeing someone else do it that way I couldn't argue that it didn't look good. And provided you're not putting these outside (lol), you shouldn't have to worry about moisture exposure. If you live in a high humidity area though, you might want to think about some kind of coating (at least a clear coat). I had thought about painting them and even stained a piece to see what it would look like. The stain looked nice (I can post a pic of what that looks like) but I already was looking at 3 weeks of downtime with the trap build and moving into my new mixing room so I just decided to leave them raw this go-around. I might stain them later however it is probably a better idea to do whatever you're going to do before you attach the fabric.
A 4' x 8' sheet costs about $25 (US) in my area and you get about 8 traps out of that. So that's about $3 a trap. If you don't want to use MDF your only other alternative is 1x5 Pine. Which runs around $5-$6 per 8' piece. So somewhere around $12+ per trap. And good luck finding straight pieces lol. Plywood won't work because you'll see the layers in the front and particle board will look like crap.
Note though you'll need a tablesaw or access to one if you use sheets. Or call around and find a local lumber yard that will do the cuts for you. Home Depot/Lowes won't be able to do it (not with any sort of accuracy).
More to come.