~/Library/Preferences/com.microsoft.office.plist has a nifty key called 2880FirstRunSetupAssistCompleted which, when set to an integer value of 1 can suppress the Office Setup Assistant. To deploy, simply install Workgroup Manager on a client machine that you have Office on and then from the Preferences->Details screen click on the + sign and browse to that file. Once imported, remove all the keys except that one if you want to and then click on the Apply Now button. Associate to users as needed.