OS X Server V10.6 Snow Leopard :: Manage Local User Home Folders?

We are using Mac OS X 10.6.8 in a classroom. Hard drive has two partitions, one for OS and apps, the other for student's files. Computers are bind to the Active Directory. Unfortunately, local home folders are on the boot parition. Over a time when apps FCP and Avid are frequently used, the boot partition gets filled with files and finally it's full. With zero kb available, users cannot even login anymore. Manually deleting files by admin is cumbersome and time-consuming task. 

I'm looking for a way to keep /Users folder clean. Putting user's home folders to server is not an option, because of latency issues etc. Unfortunately the local home folder is the default saving place when user issues the Save As command. I've tried to tinker with the User Template to lock the Documents folder but apps like Microsoft Word and Final Cut Pro go crazy when they cannot save there. Forwarding /Users to other partition does not solve the problem, it just moves the problem to another place. Logout Hook to automatically purging the files could be an solution, but there's always one hapless soul who saves his or hers files to wrong place and loses them. Or maybe a script which looks at the modfication date and deletes old files. 

Info:
Mac OS X (10.7.2), ARD 3.5.1