The Quantum III is pretty good, as I can vouch from experience with mine, though there's alzo the Zorch which is coming out later from Elektrolumens, which has a twist on-off function, a feature sorely lacking from the Nuwai. The battery life on that one's rated around an hour, estimated, though the Nuwai doesn't get that much more - 1:40 till half-power, and then an hour or so later for the rest, according to Craig's test.
Otherwise, if they straighten out the L2's states at Surefire (we've seen three different specs from three different people there), that might be an idea for runtime. It is, however, not very compact. /ubbthreads/images/graemlins/grin.gif