I took some time to add more documentation to the power supply circuit board, and a pre-drilled mounting hole in each corner.  I updated the version number of the power supply board to 0.2x, and then re-exported the project to OSHPark.com.

None of the wiring changed of course, and initial tests of the 0.1x board indicate success, e.g. when powered by a 12V battery, the circuit board puts out exactly 5V, and holds that 5V for several seconds after power is removed.  Under more of a load, that several seconds will probably be reduced to milliseconds, but that's all we need to power down the Arduino and display anyway.  My apologies for the "vertical video syndrome".