As a flashaholic, I can never resist responding to these threads.
Is it January 32nd already?
1) I am not qualified to respond to this one. See previous posts from other members.
2) My favorite flashlights used to be 3D-cell maglites. Tough enough for improvised impact weapon and good light to boot. As the years progress, however, I have switched preference to smaller lights. 2-AA mini mags (both incandescent and LED), Doug Ritter eQ headlamps, and other LED lights. They can't be improvised for impact weapons but they sure are bright and a lot easier to carry and use than those old mag-lites.
3) How about one small and light enough to be convenient to carry and not be a burden, yet make a decent improvised impact weapon; rugged and reliable; made in the USA (apologies to anyone outside the US, no offense intended); various modes (high to low output, strobe, sos, etc); LED of course; runs on everyday batteries I can find locally (AA, AAA, etc); and the reason I haven't bought anything close to this that may already be available, something truly affordable (under $25 would be really nice). Hey if I can dream I'll dream BIIIIIIIG.