I'm sure someone has this figured out.
no, not really, thou I'm following another concept. My intention is to have everything running from an SD card, thus the NAND config just to be a fall-back. IMO this at least has two advantages:
i) you could still use your approach for a backup, as it doesn't make difference if the it's coming from NAND or SD!?
ii) it's esier to make regular images from an SD card
iii) you can have several SD cards with builds going into different directs which can be scratched easily to start over again.