B&N's 1.2 firmware is built on top of Froyo 2.2. Any reason you haven't updated to B&N 1.3? If your current 1.2 is rooted, then you already have what you're asking for. If not, your options are to
root your current system,
replace it with a custom ROM such as CM7 (Gingerbread 2.3.7), or install CM7 on a
bootable SD card, leaving the stock install in place.
I have a blog post half-finished going over all the options--if I wrap it up tonight, I'll come back and post it, but those are your main resources.