I know of one off the shelf back office program that could be customized and two others for the theatre business.
The off the shelf is Real World, accounting with some POS functionality, takes some work to customize but you might be able to work with it.
Mcallister (sp?) out of Boston Mass. This company took the old GA package from Sonderling Broadcasting Corp (S.B.C., purchased by Hoyts) and marketed it.
The other is Crane Atlanta, owned by Ken and Gene Crane. Crane has done backoffice for a number of circuits.
The theatre programs handle booking, film accounting, distributor payment calculation, tax calcultaion, settlement, etc.
I'm not sure of the price range or ease of use of either of these. They may be overkill for what you need.
Greg Borr
Ready Theatre Systems