A number of readers have also reported that their local Canadian EB Games are corroborating the four-week delay. There's no official word from EA or Harmonix yet. Online retailers are prone to error, and with just a week before the game is slated for release, we hope that's all it is. Otherwise, given such short notice and such a noticeable delay, local EA offices might have a mosh pit of angry Hockey fanatics to contend with.
Update: bits bytes pixels and sprites has an interview with Harmonix where it is noted that packaging regulations (i.e. Canadian boxes must have English and French text) might cause a short delay -- though we hardly doubt that would justify four weeks of absence. It should also be noted that the PS2 version of the game is due out December 17 which, if the delay is indeed an error, would explain the origins of the miscommunicated release date.
[Thanks to everyone who sent this in!]