Here's a listing of quilt museums that might head you in one direction or another (click on the name of a museum to go to it's website).
http://www.quilthistory.com/museums.htm
Not included on that list are the State Museum of PA in Harrisburg
http://www.statemuseumpa.org/quilts05new/pages/home.htm and the International Quilt Study Center and Museum in Lincoln, NE
http://www.quiltstudy.org/.