Note from the Official AR Light Geek:
Since people keep asking-
I think I've sourced out a great bike light for multi-day AR.
I've been speaking with Dinotte lighting.
They now have a 5W LED, the 200L. It's tiny and very light. It puts out 200 lumens with a brand new type of LED, which is over 3X as bright as a Princeton Tec Apex 3W. It can run on 4AA lithium batteries, and they can modify it for AR for 2.5 hours on high, 5 hrs on medium and way-long on low. You can get extra AA battery holders too, or lithium rechargeable packs. This light is not on their website yet.
http://www.dinottelighting.com/index.html
They also have monster 500Lumen LEDs.
No finanical interest etc...