Sorry it took me so long to notice a reply. I've been in and out and not checking the forum as often as I'd like. There's a modder who posts regularly on Candlepowerforums who does some nice mods to Arc-AAA lights as well as some high-power mods to 2-cell Maglites. There are various choices, and the price of modifying your existing ARC-AAA can vary from around 30$ to 50$ depending on what you want done. If you don't have an ARC-AAA I believe he will also provide that for a reasonable fee. You can get a single stage luxeon set at either 3/4W, 1W, or 1.5W output. Battery life for the 3/4 watt mod is between 70 to 90 minutes depending on the battery type you use. The higher power 1 & 1.5W lights get shorter run times. A 2-stage mod runs $10 more, and you can select a low level of either 30ma or 60ma drive to the Luxeon LED. The 60ma is a nice setting, and runs between 6 to 7 hours. Another service provided is to polish the reflector ($3) and to regrind the reflector to a parabolic shape, which increases the hot-spot and throw a bit ($10). I have a couple of 3/4 Watt 2-stage models, a 1W model, and I had him modify an ARC-AA with 1.5 Watt drive to the luxeon and a 90ma low drive. The AA ARC is larger, but the output is fantastic for a single AA battery pocket light.
These lights are well made and have a nice "Wow" factor" when non-flashaholics see how much light can come from such a small package", but for EDS there's nothing wrong with a plain everday stock ARC-AAA. Practically indestructible, and with a lithium battery installed they're almost weightless.

Miller Mods ARC-AAA Mod Post