Dreyers Grand Ice Cream, in Oakland, California (where I work while
attending San Francisco State Univeristy's Museum Studies graduate program),
has quite an extensive corporate art collection. Their phone number is
1-800-888-3442. They deal exclusively with an art consultant, Suzy Locke
(who is also on the Board of Directors at the Judah Magnes Museum where I
am interning this summer!) Her number is 510/547-5455.  She works with
several large Bay Area corporations placing art in their collections.
Good luck,
Candy