This comes from frequent contributor Foolsdragon:

Well, I didn't want to believe it, but it's true; the hold up was because the VPC didn't have the 2005 stickers ready! We just got an e-mail from our regional rep saying that the ship blocks have been removed and they're going to start releasing cars from the VPC to the dealers.

I don't know if the stickers were delayed because of not enough information or anything like that. For all I know, they just didn't have any with a new design ready to print on.

Update: Well that was fast! We now have confirmation from two dealers that they have recieved their first '05s. Aparently the first batch went out unnoticed a few days ago.