Yeah having it continue the boot post-fastboot is an easy fix. I didn't realize you could continue once fastboot ran. All you'd really have to do is find the menu option in.. I think it was mmc.c... and then just have it call another boot profile after it executes fastboot (or re-run the menu). If you need help with this I can show you how to do it.
Incidentally a few days ago I posted a first attempt to an update to the menu, based on refinements to cyanoboot nookcolor from tonsofquestions
and then adapted to the NT. . Chrmhoffmann was supposed to take a look, but I don't think he had a chance yet. It's up on goo-inside.me if someone wants to try it. Somehow I'm guessing it will crash hard, but if someone is feeling adventurous, there's a flashing_boot.img up there which includes the source.
The big difference is basically that it will grey out menu items that don't apply (based on whether the files are available on the sdcard), but there are some other optimizations to the menu interface as well.
That plus the fastboot recover I think might warrant a new "major" release. I hesitated to post it until someone tested it-- I still dont' have a nook tablet. But since a patch to the previous source is available, if it's not working, someone might want to debug it as necessary.
There is also a discussion on the cyanboot nookcolor thread about whether a portrait or landscape configuration is more desirable. There is a horizontal version implemented, but consensus seemed to be portrait was preferred.
Anyway, the probably-will-crash experimental version, along with the source diff, is here