Thanks to Charles W. Bailey, Jr. for pointing me towards a listing of Collaborative Digitization Projects in the United States. (As the saying goes, ask and you shall receive.) These are ongoing collaborative digitization projects that focus on cultural heritage materials, not necessarily statewide projects. The list is maintained by Ken Middleton at Middle Tennessee State University (MTSU). MTSU and Ken are also actively involved in DigiStates so it makes sense that they would maintain this list. The list was updated in June 2004.
By the way, the list contains one project in NYS (Hudson Valley Heritage), which is a cooperative project in the lower Hudson Valley (near West Point).