For some variety in your faculty portrait display, how about displaying
portraits done by your students (of the faculty) instead? Maybe not
permanently, but it would be a fun short-term display.
(If you go to the local frame shop for mats, I hope the school will pay for
it -when I was framing I had so many requests for "free matcutting for the
school" I easily could have done it full time - even a very insistent
request for a double-mat with enough openings for an entire senior class)