What happened was this:
I was (and remain) interested in reducing current consumption. I used the fuse calculator at:
AVR Fuse Calculator for ATmega328P.
My intent was to keep the L fuse at 0xff, and change the H fuse to 0x49:
7 RSTDISABL = 0--I wanted to be able to remove the RESET line pullup
6 DWEN = 1
5 SPIEN = 1 THIS WAS MY MISTAKE
4 WDTON = 0 In my particular application I wanted the WDT to always be active, even in sleep mode
3 EESAVE = 1
2 BOOTSZ1 = 0 Default size
1 BOOTSZ0 = 0 Default size
0 BOOTRST = 1
So the fuse calculator produced a value of 0x49. I called up AVRDUDESS and wrote it out to the chip..."GAME OVER MAN!"
But I have the ability to remove whatever pullup might be on the RST pin and then pull the pin up to +12v if that's all that's required. Creating a timed pulse will be a bit harder but certainly not impossible--I have one more unbricked Chinese Nano board that I can program to output a pulse to a transistor. I will investigate further...