I honestly think u are done with your project allready, but google search brought me here, while lookng for something similar ...
For everyone that cant get a hold of the 6921, there is a chance to get it.
those guys were kind enough to send me two of those chips
free postage, and im from Slovenia. Im guessing no one here has ever even heard of it haha.
anyways, the package u want, might not be available for sampling, but try to get the that sits in the PLCC socket, or even better get a through hole one. I got the AUI+, that is freakishly small, but its nothing a little solder wick couldnt fix