It is true that the deadline to declare DI intent is December 1. However, this only becomes effective the following school year. UND could not declare it's intent by December 1 and have it effective for the 2004-2005 year. The reclassification period would begin with the 2005-2006 school year.
So if UND notifies the NCAA of it's intent to go DI by 12/01/04 they will only be 2 years behind NDSU. However, if UND notifies the NCAA by 12/01/05, which is more realistic, they will be a full 3 years behind NDSU.
I believe it will be a minimum of 3 years difference, and more than likely 4-5 years. And don't underestimate this difference and the impact on fan support, fundraising, corporate sponsorships, and recruiting.