Hmm, my previous experiences with running 12v to the barrel connection was the vreg got really hot, even when only powering a couple LEDs limited to ~5ma each. I will attempt it again though to see if I have better luck this time. If not, I'll use two supplies. I don't have a 5v switching regulator around, that would be the ideal solution to bypass the vreg entirely, though I'm not sure if that would introduce em noise problems.