The one problem with projecting what the Big East may look like is that we simply don't know.
In order for the Big 10 & SEC to expand to 16, there is no doubt in my mind that those two conferences will take 3-6 ACC schools to get where they are going. Where will the ACC go to replace its lost members? The Big East. WVA, Pitt, Syracuse, & Rutgers would all be desirable for the ACC and would be likely replacements for lost ACC schools.
My best guess is that once the PAC 16, Big 10, & SEC have settled on who they want, you will see a fourth "leftovers" BCS conference emerge. The TV deal won't be incredibly lucrative, but there will be some good members and it will allow the current BCS AQ schools to keep their status. I could see it growing to as large as 20-24 schools just to make sure everyone gets in that deserves to get in. Perhaps it could look like this:
Southwest Division:
Hawaii
BYU
Houston
TCU
SMU
Baylor
Midwest Division
Iowa State
Kansas State
Kansas
Louisville
Pittsburgh
West Virginia
Northeast
Syracuse
Uconn
Boston College
Rutgers
Cincinnati
Maryland
Southeast
Clemson
Wake Forest
Florida State
Miami
USF
Georgia Tech
The above was off the top of my head and jotted down quickly, but it is what I see happening....basically, every school that gets "left behind" by the SEC/PAC/B1G will band together to form a somewhat national conference to maintain their AQ BCS status.