A couple of months ago I had an idea for a very compact but efficient
pocket flashlight. The idea was to use an offset-fed parabolic
reflector (like satellite TV) rather than the traditional flashlight
design. Computer models indicated it would work well. Then I got
sidetracked on other things.

I've revisited that with a quick 'n dirty experiment. It seems to
work on the bench as well as in the 'puter.

More at
http://users.goldengate.net/~dforeman/tinylight/