LED Light connected to external/belt battery pack?

Does such an animal exist? I'm not looking for some huge honking HID light or something..just a really bright LED light that connects via cable to some type of external battery pack that can be either worn on a belt or perhaps put in a backpack, etc. I don't have a particular application for it I just got to wondering if something like this exist. I would think it would in some configuration or another. If someone were willing to deal with the battery pack itself it would seem you could get a lot of runtime on a very bright light using say 6, 8, 10 or maybe 12 (or more) of the 18650's or something like that. I've done some searching but haven't turned up anything. Has anyone seen anything like this?

That setup is somewhat common for headlamps. However, external packs are usually very cumbersome, and simply carrying spare cells is usually much more convenient.

I have the Foxfury Sportsman water...talk about stadium lighting for yuor head...22 white leds, and 4 green on the sides to correct color rendition. Auto sensors that shut the light off in daylight...and waterproof to 30 feet I believe? Runs off 4 aa's and gets pretty good runtime.

Nitelite comp makes a LED headlamp assy that attaches to its 12volt & above belt battery packs. Its a miners style light. http://www.huntsmart.com/hunt/Hunti...m_Nite-Lite-5100-Style-LED-Headlamp_HLED.html Pelican still makes the heads up 2660 that has a belt pack with Incan and LED