Maybe you can pick up a light with variable brightness settings. Lots of mid range lights have low (moonlight) medium, and high settings.
Since you said you want to cobble something together perhaps you can check out the quark by 4sevens. I believe the quark takes CR123s but can come in a AA version as well. It also has pretty good reviews and feedback on candlepowerforums too as they supposedly helped design the lights with their input in the manufacturing process. If anything you can also use if for every day carry when not gaming as well.
I personally carry the preon 2 every time I go out and have never looked back, and it has never missed a beat.