Nebraska used to be AAU until they were voted out. UMD and Rutgers both are.
Good luck, since membership "is by invitation", it seems to have much more subjective than objective entrance criteria.
Article on Nebraska getting kicked out (stabbed in the back by UM and UW).
http://journalstar.com/news/local/ed...39ec5acb4.html
Since AAU membership, according to the article, seems to be required, UNC/Duke/GT would be the obvious candidates if the B1G did decide to raid the ACC again.