Thanks for the answers about the 6 cell pack used for the Chinese 4x18650 lights.

Perhaps a related question: all things being equal (number of LEDs and batteries), are those super long flashlights on 3x or 4x 18650's likely more powerful (brighter) than the stubby flashlights running on the same number of 18650's? (I have a stubby one which is very bright, but never tried the long type). Example: