Hm...what am I thinking of...I know someone on the forums (Jim, maybe?) was doing a group buy of a horrendously expensive lamp for Maglites, a couple years ago. IIRC, it was around $25, or a little more. I have also seen the Xenon bulbs, and you're right that they're not very expensive.
I firmly believe that carrying a task light and tac light is the way to go. The Twin-Task light come close to being able to "do it all" with long endurance with the LED's, and bright, well-focused power with the Xenon lamp, but "the button"
is not optimally placed for emergency usage.
John, used to carry a 6 cell Maglite years ago, until he discovered that a 2 cell met his needs just fine...until his tree stand was surrounded by a herd of wild pigs just after dark, and he had cheap Rayovacs in the light! DOH!