One time when I was surfing around, I saw a site
that had photos of a diy frame and its construction.
(sorry I guess I didn't bookmark it), it was assembled
much like Larry's post the only difference, and
I thought it was quite a good idea, was that the
guy had used clear christmas tree lights to light
it. -very inexpensive, and in the photo at least
the ooster and the milk-white plexiglass diffused
the source enough that you couldn't see the individual
bulbs.