I can confirm the dual boot option works. I have been running each latest (nightly) from CM7 along with nook stock (rooted). You would be able to boot into either straight from eMMC. Once you've done it correctly you just hold "n" and power to boot into stock or just press power to boot into cm7 or any other build you have installed. CM7 stable will install just fine however nightlies need to be modified slightly. Not sure if this has any negative aspect to it (haven't experienced anything) but I simply open a nightly with 7-zip, delete "u-boot.bin", resign the package, copy to SD and install from CWM. The main thing to look out for is the replacement of "u-boot.bin" as this causes the dual boot to be disabled. If you, or anyone needs help with this just pm me and maybe we can set up a gtalk or something. Most details are found throughout xda, you just have to look.