Dealextreme.com has all the cheap line of P7/MCE lights.
These are the branded P7/MC-E:
1. Tiablo ACE
2. Jetbeam M1X
3. Fenix TK40
4. Dereelight MC-E module
5. Lumapower mvp turboforce
4. Solarforce L900
5. Microfire Explorer series
6. Eagletac megalight -not avail. yet
7. Olight Triton -not avail. yet
Budget choice: get the DX aurora 2-modes p7.
Pure brightness: get the Tiablo ACE.
Modes, AA cells: get the Fenix TK40.
Brightness, modes and style: wait for the eagletac Megalight
Sorry, but the most are multi cell lights
Only the ACE can run with one cell, but only short time, becaus the "over discharge protection" is set to 3,7 Volt and this is to high....
There are some one cell lights on the market, epsilon, KD/DX lights, but all not regulated and so the brightness drops quickly, if the voltage drops:thumbsdow
Jens