I've visited your website several times, Bill. Neat stuff!

If you haven't tried a 3-watt Luxeon in a reflector from a 2 D-cell
Maglight, I recommend it. It makes a pretty impressive light.
Pretty narrow beam, but it lights up treetops 100 meters distant. It
compares quite favorably with a 6-volt Everready lantern.

I used a Luxeon emitter (not a star) epoxied on a 3/8" dia aluminum
post so it could reach inside the reflector to the focal point.
There's a 2" square aluminum heatsink at the back of my post, but it
could also be a disc of the same diameter as the reflector.