In terms of gluing foamcore together, there is only one adhesive I know of that really works, but I can’t remember the name. It comes in a purple squeeze tube — you apply to one or both sides and hold or tape the piece together (using blue painter’s tape works best for easy removal w/o tearing the paper). You can get it in an art supply, crafts, or hobby store. I’ve heard that Liquid Nails will work, but your run-of-the-mill, standard glues either will dissolve the core or simply not bond. The glue has to be an adhesive formulated for use on polystyrene.

Also: if you hit up an art supply store for the board (or a craft store, like Michael’s), you can choose from many colors — including some that are reflective (not sure if that’s a requirement, though).

This looks great, though. Flickr photos are helpful (and the CFL bulbs shot rather artistic, too).