I'd be interested in hearing more about this Dave (or is that Mr Amazing?), let us know how it turns out.
*blush*
It turned out great! I tried several attempts myself at formatting the card properly, or by using some of the other known tools for creating CM7 boot SDs, to install the stock ROM to SD. Nothing worked, the closest I got was renaming the stock ROM zip and taking out some of the extra crap (intro vids, demo books, etc) until the stock ROM was small enough to fit on the CM7 SD card, and I used the CM7 boot SD tool to inflate the ROM onto the card.
While I was successful in getting it to extract to SD, I couldn't get my Nook to boot it. I later learned about the /ROM partition (and there's another I can't think of ATM) that are required for a stock Nook to boot which aren't present on the CM7 boot SD,
So I whimpered my way over to XDA and asked, and after waiting a day and bumping my thread (which the bump was ultimately deleted by a mod lol) someone gave me a link that made me very happy.
[ADV][DEV][CWM]Copy Nook Stock to SDcard Image[5/9] - xda-developers
I backed up my Nook, tested my backup, and then wiped every partition on the Nook. Using a CWR-flashable copy of fresh stock unrooted v1.2, I returned my Nook to factory specs. Once the stock ROM was installed, and I had booted it to finish seting it up with my BN account, I powered down and put in the SD card I made with the above link. It took around 10 minutes, but the recovery program on the SD card successfully copied the Nook's eMMC to the SD.
After that, I reboot with a regular CWR SD, wiped all partitions again, and restored my back-up. I let it reboot to make sure it restored correctly, and once it did, I powered it back down and popped in my SD.
It booted fine! Can't even tell it's running off SD. It is a class 10 card, though... Anyways, I went by work last night to test it, and it picked up that it was inside a B&N just as I had hoped. I was able to read for free and even took advantage of the coupon for free fresh-baked cookie with Frapp purchase.
