Sandra, the Foundation Center has a Nonprofit Collaboration Database
that would be of great use to the museums you mention, as well as any nonprofit interested in pooling resources and talents with another. The database provides information about more than six hundred and fifty nonprofit collaborations -- you'll be able to search by map, basic topics, or key words to find examples of partnerships that relate to your museums' experience and goals. For example, here's the record we have on file for a collaboration between a museum and a liberal arts college
The Foundation Center has a host of other resources about nonprofit collaborations and mergers. Visit the Nonprofit Collaboration Resources
page for information about nonprofit partnerships with grantmakers; interviews with sector experts about nonprofit mergers, alliances, and restructuring; case studies, research, and much more.