Cloudpeak, the main reason I use a tumbler is for it's easy of use and efficiency.
Dump the cases in, turn it on, come back in a few hours, nice clean shiny cases.
I tried the case wash thing a few times, to be honest, it wasn't worth the hassle to me.
Check out Edwards home build one (link above). It's basically the same as a "store bought" one. They are very simple in design and are more or less, a big bowl with an electric motor underneath, with a metal plate mounted on the end to throw the motor out of balance, thus, causing it to vibrate the bowl.
The ones you buy have a lid, but to be honest, I never put the lid on mine.
Hint: The little motor underneath looks JUST like one from a cheap bathroom exhaust fan (about 10 bucks at Lowes).
I don't know if you can buy the parts needed to build one as cheap as you can buy one of the cheap tumblers from Midway, but if you have the stuff laying around, it would definately be worth looking into.