I've been thinking about building a light box for a couple of reasons--less glare when I'm using an Ott lamp because we haven't seen the sun in months and the snow is 3' deep, a clean, uncluttered background--but I just haven't done it yet. I know they're not difficult to build, but I came across this little set-up for $29.99 and free shipping at Adorama.com. Here's the description:
Adorama De-Shadow Box, Table Top Photo Studio In-A-Bag, with 16" x 16" Soft Light Box, Halogen Lamps, Blue/White Background Sweep, Custom Carrier & Camera Stand.
It seems to have good reviews, and I can guarantee that if I made my own, it wouldn't look as neat as this one. It may not even look like a square or a box, for that matter! It folds flat for storing and it comes with the lighting and camera stand too. I'll report back when I receive it, so here's hoping it's as good as it sounds!