Mine's not completely done yet, but I've got it about 90% complete. I purchased an 8' square canopy from the local sporting goods store. It's not huge but fits nicely on one side of my garage. I cover the walls with a roll of clear painter's flooring. You can get a roll of 10'x40' for $10 or so at a hardware store. Right now it's just attached with clamps, but I plan on using velcro to allow easy removal of the walls when they're not in use. I bought 4 shop lights from WalMart for $7 each and hung them at each corner. Now all I have to do is cut an opening in one side to place some box fans with filters attached and holes on the opposite side for some air input. The nice feature is that it can all be taken down in a matter of minutes. The canop folds down and has it's own carrying case.
I used it last weekend to paint a helmet. I just rolled up one of the walls to allow the box fans to exhaust the fumes. It seems to work really well. There was plenty of light and there was no dust on the helmet. Once I get all the filters in place I'll be sure to take some pictures. Time will tell how well it works.
-Stretch