This is late, sorry, built it about 3 weeks ago but didn't get around to uploading my camera pics.
Anyway, with instructions from The Cheap Vegetable Gardener I made my own LED Grow Box. I recommend following his instructions, they are good. Here are some pics of the construction:
measuring out the size for drilling
my spade bit made a nice little collar that helps hold the lights steady w/out glue
almost done with drilling, yes I use unsafe methods...
hmmm, my 70 LED set has 75 lights...

she's a bit purty in use...
I used LED xmas lights 50% off two weeks after New Year's. I couldn't fin a set of just blue LEDs, but I got a multicolor one which I haven't added to this yet.
So far I like it. The first week I made it I had also sowing seeds indoors and several sprouted within days. It was still in the 40's overnight so I brought them all into the box from about 8pm-7am. I think it really did help, but I can't say for sure it's boosting my babies. Perhaps an experiment with a control set of seedlings is in order...