My BD Moonlight also has the contact problems you describe, Debra. My quick fix for it is to use a clunky rubberband and twist-tie arrangement to force the wire into an angle that allows the light to work, but to do this I have to wear the battery pack over to the side a bit instead of at the back of my head. The light is the 2002 model, but I only used it about 100 hours and never abused it. Time for a different light.
Regarding my hoped-for ideals in a light:
* LED(s) that would allow me to run on rocky trail without slowing down much, but that has a lower setting for camp use. Battery use for technical/runnable travel: 15-20 hours. Regulation would be needed, I think.
* A combined high-power spotlight capability, probably xenon, that could illuminate far ahead for occasional navagation puzzles.
* Pivoting head, ideally detachable for hand use. I experimented a couple nights ago and found that indeed, as Kevin Sawchuck wrote, one can see better for technical running and power walking with the light at hand level. Not only because of better "shadowing" but also because varying the left/right angle of the light sometimes illuminates better foot placements.
* Use of 123 lithium photo batteries would allow the above ideals for about 4 oz. (Ref. the tactical lights by Surefire and Arc.) Maybe even a design using 2 or 3 AA lithiums could pull that off.
I'm considering buying a good hand-held LED light as my walking/running light, and carrying a tiny light like the Ion for camp tasks. Or even lighter for camp work, I may try gluing velcro to my cap's bill and to a microlight (I like Inova's brand best). For night walking, a reviewer from Backpackgeartest.org sewed small elastic straps onto his bill to mount a Princeton Tec Impact LED handheld. An option for relatively smooth trail even when running, if the hat stays stable enough.
Are there any plans to review handheld LED lights here some time in the future? Ryan, your methodology and analysis are much better for backpacking purposes than those used by the several LED light review sites.