Thanks for the info so far, everyone. It's been considerably helpful. As an update, I doctored up a couple old Streamlight Batonlite's with a disk of colored plastic (one red and one amber) inside the lens. Both have really quite nice soft but broad beams almost perfect for preserving night vision. The amber actually appears significantly brighter but still dimly but clearly lights up almost the whole wall I'm shining it at (when my vision is night adapted).
While in Fry's today in Manhattan Beach, I also picked up a red LED Inova X5T for $29 which is very bright, even with some frosty scotch tape over the LED's. Tonight I'll get a chance to compare it with my doctored Batonlites. I was also fairly amazed to discover the Inova 24/7 on sale there for $19 (most places around here have them for about $39). Incidentally, this is a great light with 3 colors of LED's (white, red and amber) which are quite bright, and one low-level setting for the white LED's. It has one whale of a trippy 3-color "distress strobe" mode. Instead of springing for the red LED Lumamax L1, I picked up the X5T and the 24/7 for less than half the cost. I do believe though, as UnknownVT suggests, that both the X5T and the 24/7 are going to be a bit bright to preserve true scotopic night vision.