User blog comment:JackfieldsA113/Mass Effect 2 Ultimate Edition?/@comment-2130363-20110531043136/@comment-1221773-20110531043845

Didn't Microsoft recently upgrade their disc format, though? I think the new discs can hold an extra gig. That might be enough to squeeze in all the DLC.

Alternatively, BioWare could simply pack a code (or codes) that unlocks all the DLC with the game as it is. It would be frustrating for those looking for the DLC in disc form, but it's an option. Epic Games did this with the Gears of War Triple Pack.