The crux of this discussion is that a school from the ACC becomes available despite the exit fee and GOR. This seems highly unlikely; however, for the sake of this discussion let's say this is the case as I agree with you that the Big Ten is still looking toward the East for further expansion.
The Big Ten may have interest in UVA and the conventional wisdom is that UVA would be the next target for Big Ten expansion. However, it is my impression that UVA is content in the ACC, values being a conference partner with UNC and has no interest in the Big Ten.
There is another ACC school that is rarely mentioned as a Big Ten expansion candidate but could be a better fit for the conference than most would think: Virginia Tech. Please everyone put away the slings and arrows for a moment. I realize this is a UConn board but you need a partner for the Big Ten so let me explain my rationale.
Virginia Tech is a public land grant university and of their 25 peer institutions 10 are or will be Big Ten universities. Virginia Tech has a larger enrollment than UVA. Virginia Tech has larger total research & development expenditures than UVA as well as Iowa, Rutgers and Nebraska. Virginia Tech is not AAU but has a strategic plan in which the university anticipates " that approximately three to five years would be required to approach the impacts necessary to make us more American Association of Universities (AAU) competitive."
Virginia Tech does not have historic ties to the ACC conference since it joined the ACC in 2004. The conventional wisdom is that Virginia Tech would just be a candidate for SEC expansion. However, Virginia Tech, through prior membership in the Big East, has a history of competing in a northeastern conference and their OOC football schedule features upcoming games against Ohio State, Purdue, Wisconsin, Michigan, Penn State which indicates at least an interest in competition against Big Ten teams.
It is a concern that future Big Ten expansion must include a football addition. Although not on the level of historic success achieved by Penn State and Nebraska, with 6 BCS bowl appearances including 1 BCS national championship appearance Virginia Tech would provide this football addition. The addition of Virginia Tech as a football addition coupled with UConn as a basketball addition is another consideration for the Big Ten if the ACC exit fee and GOR could be overcome as well as any political resistance to a Virginia Tech and UVA separation.
Since I have taken up space on a UConn board touting the idea of Virginia Tech to the Big Ten, please feel free now to fire away at me and my idea with your slings and arrows.