When I was working in a corporate collection in the early 80s there were two
associations of corporate art collectors - one called NACAM (National Assoc.
of Corporate Art Managers?) and another I can't quite recall.  Carol
Ballard, who now works for Christie's, was then director of the Blount
Collection in Alabama, and very involved with one of the associations.  You
might try her for information, she is at: 334-244-9688.

Also, there is one book on the subject, you may be aware of:
Art at Work: the Chase Manhattan Collection, Marshall Lee, ed. ISBN
0-525-24272-4

And, lastly, Mary Ann Craft used to organize workshops for corporate art
curators at the Pittsburgh Grad School of Business+ADs- she later became the
editor for ARTnews' Corporate ARTnews newsletter.

Hope these help.
Celia Walker
Cheekwood Museum of Art, Nashville, TN