Here's an update for those interested.
On the front is a Heiland bulb release that's been modified to fit a larger screw; this piece will be the "activation switch". I didn't want to use this part originally because it meant drilling a big hole right in the middle of the "Busch B-C" stamping, but I gave in when I realized it was the right part for it.
For the back I decided to add another piece I got from Custom Saber Shop. It's a nut shaped like a Graflex button that went with a button sold on the site. I didn't want it permanently attached, and I didn't have a bolt with the same threading, so I cut off the threaded portion of the switch. I epoxied the threaded section with a washer to the main piece, and added a piece of thin metal tubing scavenged from an old ac adapter plug. I had to pry out the bulb release lever so it could fit properly, then added some foil tape to the side walls so more like could reflect in. As a result the spring inside is still faintly visible in the hole, and adds a little depth to it. I'm thinking of adding a clear piece of plastic over it.
I think I'm pretty much done with the upper section of the hilt aside from possibly painting some of the parts black. I may also ad a small piece to fill in between the activation switch and the fins above the clamp box. I'm also keeping an eye out for something to dress up the emitter a bit. Still debating what to do with the grips. I haven't ruled out T tracks, but I'd prefer something a little more visually interesting/unique, which is why I'm considering the rails in the first post.