I'm not complaining, but I don't know how this kind of progress in a few days could have been feasible. Porting the drivers for the camera, WIFI, NFC, etc... would take weeks with a good team of hackers. Especially seeing as the SDK has almost none of the drivers that the NS4G need to run. This is a near flawless build of Ice Cream Sandwich from an SDK. I'm not too thoroughly well read on the history of SDK porting on every android device, but from my understanding something to this scale really hasn't been done before... Definitely not until AOSP.
EDIT: Also, I own a Motorola Xoom, so I'm speaking from experience. There are a LOT of resources that are identical to Honeycomb's in this port. The ICS SDK revamped most of them. I know that a lot of gingerbread resources have been found within honeycomb after some disassembly, but I don't know if the opposite is true.