I would be in for one of the extension tubes and 4800mah battery packs in addition to the HDM6 starter kits. I agree that 95% of the time , the 40 min run time will be more than suffficient, but on say an outdoor camping event(boy scouts) where there is no electricity available, or a search and rescue operation, the longer run time could come in handy. I realize you could also have the stock battery holder filled with fresh 123's too, but when hiking, you want to keep weight to a minimum and space is limited.
I just had an idea,an extension tube with tritium inserts and maybe the charging jack also if there is room,or could be made so there is enough room.
I need to stop stirring the pot, I know,so I will just let you guys work things out.