From your post I did a quick search and found this one that list a script that I think is what you are after. http://www.linuxforums.org/forum/arc...p/t-46726.html
I did not look over the script but my thinking is a script that runs from cron every hour maybe that looks in /home and sorts it size. Then it can send you an email of the output or maybe the tail of the output. Or go farther and check the output for vaules higher than you want and just email that to you when it is over the limit. Less email this way. The script in the link might be what I am talking about.
Somethings are the simpliest.