According to Yahoo Sports, Note Dame athletic director Jack Swarbrick has been in discussions with the ACC about a potential agreement to play in the Orange Bowl during seasons the Irish are good enough to merit a top tier bowl but fail to make the four team tournament to crown a MNC.
The face that these discussions have been with Swofford and the ACC instead of the Orange Bowl directly is a good sign, dune that implies the discussions are most likely of a business nature, regarding revenue sharing and the like. The Orange Bowl has already expressed interest in the Fighting Irish, and the fact that talks are already taking place between the potential business partners means things are moving quickly.
Inking a deal with Notre Dame for the Orange Bowl would be beneficial for the ACC on multiple levels. First, it gives the Orange Bowl added gravitas, matching a major conference champion with one of the most historically prestigious programs in college football . Second, it gives the Orange Bowl unmatched flexibility in selecting opponents.
If the Irish fail to meet the selection criteria for the Orange Bowl (I'm guessing nine wins and a top 12 finish), then the Orange Bowl is free to fill that spot through a truly "at-large" process. Contrast that with the agreements the B1G and PAC-12 have with the Rose Bowl and the Big XII and SEC have with the Champions Bowl to send an alternate selection from the conference should the champion make the tournament. It's very easy to see one or both of those bowls becoming a matchup of also rans. (Especially the Champions Bowl.)
Should the Irish either stumble or make the tournament, however, then the Orange Bowl would be free to select the best available opponent, which could be the Big East champion, the champion from one of the other mid-majors, or another attractive team from one of the "big five" conferences.
Nothing is set in stone yet, but the scramble to remain relevant in the "tournament era" of the BCS is on. Notre Dame either has to join a conference (not happening) or ink a deal directly with a top tier bowl. The Orange Bowl, with its opportunity to play a major conference champion, provides the most attractive offer left on the table.