As to side loaded videos...B&N specs say mp4 is the supported format so I gave a few files a test drive.
Case 1: Simple 30Mb mp4 file = played fine. There is some lag to start
Case 2: HD TV grab converted to mp4 = played fine, excellent rendering...even longer lag
Case 3: Large 720p video (560Mb) mp4 = NC reported that this video was not supported
Conclusion: I don't know if it was because it was the frame rate or size or what...so if anyone has some ideas I'm all ears.