Just got the light delivered today. Got the battery charged up, and holy COW this thing is bright. There's the little bit of a center spot, but the evenness of the light is just awe-inspiring.
I think I'm going to keep the Cygolite for multiple errand runs, but the L&M battery does definitely work fine in the bento box. The bump of the single cell on the bottom of the battery pack seems to hold it firmly in the bento box enough that I'm not too worried if I do run it on the bars. The helmet mount is definitely very cool, might just keep it there so that I can use it seamlessly between the two different bikes (commuter+road).
I can't believe it, but this might have been a pile of money well-spent. The legends were all true!