Or, for something you can get done today, assuming you have a 3 cell Krypton (not Xenon) bulb in there now, remove the 3 D cells and replace them with 4 C cells. The tailcap spring should be cut down, but you can make it work.
This is nearly as bright as the 3x123+KPR113 mod in the 2C body, but with longer runtime and potentially cheaper cells.
And you can always sputter the reflector.