2nd Foursevens Preon P0 (2 modes). Another option, albeit a bit more expensive, is the Peak Mule Eiger (single level, or available with QTC). An even more expensive option, with less output and you'd have to wait for the next batch (way down the road) or make a WTB thread for one, is the Muyshondt Mako Flood (2 stage twisty).
You might want to also consider the Fenix E05 (single mode). It's not a mule type (pure flood) light but it uses a diffuse optic to spread the beam out evenly without a hotspot. And on that note, also consider the Veleno Designs Quantum D2. It also uses a diffuse optic to spread the beam out and QTC to control output.
All of the above lights use 1xAAA battery with the exception of the Quantum D2 - it uses a 10180 li-ion battery. The Eiger can also use this cell as different bodies can be purchased for it.