I bought my own nook color on saturday, there doesn't appear to be a factory image that can be restored. My new nook color came with version 1.01 preinstalled. Before turning it on the first time I put in nookie froyo and did a dd of all 8 of the stock partitions. Below is the zipped up .img files of mmcblk0p1/mmcblk0p5 (boot/system) from a stock untouched 1.01 nook color. I am also including the factory.zip. This should be enough to restore a bricked nook color with a corrupted boot or system partition. Many people have been able to restore to stock by just using the boot.img because after 8 failed boots it will do a factory reset.
To make this work you must have ADB working first. You may be able to get this to work on ADB Wireless, but I don't recommend it. For instructions on getting adb to work with the nook color go here:
To use these files unzip them to the sdcard portion of a nookie froyo sdcard, or just about any other rom that runs from the sdcard and run the following commands in an adb shell:
dd if=/sdcard/boot.img of=/dev/block/mmcblk0p1
dd if=/sdcard/system.img of=/dev/block/mmcblk0p5