Help is on the way.
This pile of utilities, images, and scripts will boot your Nook into CWM recovery entirely over USB. Your eMMC can be trashed and SD card missing, but you can still get into recovery. This is kinda rough, and Linux only for now, but a Windows version is in the works.
-PC running Linux (x86 or x86-64 with 32 bit compatibility libs)
-Nook Color plugged in w/ USB
-this archive unpacked: nc-usb-recovery-0.1.tar.bz2
-turn off NC
-turn on NC