Disk quotas on INBOXes

[Ashley M. Kirchner]

    Our user e-mail INBOXes are sitting in /var/mail/[user].  Does 
anyone know of a way for me to institute per-user quota on their 
INBOXes?  See our problem is that while I can apply user-quotas on 
/home/[user], that doesn't take into account what's on /var/mail/[user] 
... and some users are leaving their e-mail sitting in their INBOX 
because they don't want to eat up their user quota.  So, I want to limit 
the size of their INBOX file as well, through quotas.

    Possible?