thanks, guys!
answers:
at 2 amps, I get a little heating but not too much. I haven't really played with anything more than that yet, but I imagine it will require some more heat sinking.
switch in the front was a compromise: I originally wanted it on the side, but as the machinist was doing this as a favor, I didn't want to ask him to make yet another cut (a flat section for the switch to mounted on). I kind of like the way it looks now though. As far as 25% smaller, a 25% reduction in surface area on the front face doesn't end up making much difference to the overall dimensions.
I turn the light down or put my hand in front of it for oncoming bikers :)
google sketchup is free, but the pro version is $$$$