Using Cases as an internal helpdesk for Salesforce.com users

I’m trying to configure cases so that my SF users can open cases from one team to another. For instance a sales person needs a contract reviewed by the legal department etc. But, the ‘Contact’ is required on the Case page layout? These would be cases that have nothing to do with a Contact. I don’t want to have to try to recreate all the Case functionality in custom objects just because I have a few types of Cases that don’t involve Contacts. So is there some way to get Contacts off the Contact page layout?