I had my son choose some materials from the parts bins in the shop, but we had some trouble putting them together. I had a number of pieces from unfinished projects handy, so we made some quick replacements. Its hard to see, but there is a blue crystal suspended in the center of the gun.
Here it is lit up. The light is hidden in the barrel piece and is stays on until turned off. There is an opening cut into the bottom of the barrel to access the switch.
Here is a view of the gun on a less busy surface, before staining the handle. I had been toying with a petite handle that had a door in it, to house a setting switch, or dial or something, but it didn't happen, so it was sitting on the work table. It was just the right size for littler hands.
If I wasn't in a hurry, I would have sanded the handle and do some masked painting on the body to limit the light bleed; but all-in-all, it came out pretty cool, and my son was happy, which is really the whole point.