These should give you a place to start:
http://www.lansweeper.com/Forum/yaf_postst9499_Microsoft-Office-2010-Report.aspx
http://www.lansweeper.com/Forum/yaf_postst8881_Computers-with-Multiple-versions-of-MS-Office-Installed.aspx
http://www.lansweeper.com/Forum/yaf_postst10568_Report-request---Microsoft-office-and-Operating-system-installs.aspx