A PHP command line script is available, perfect to be ran as a nightly cron.
It requires, CURL, and ability to run PHP command line scripts.

When ran it verifies that sites listed in your installation are linking back
to you. If a site's return link can not be found, an optional email can be sent, 
requesting they restore your link. If after 3 subsequent checks, the return link 
is still not found, the site is removed and an optional email notice is sent.

Both email notification types use an inline template for easy customiziation.

This will be my first commercial add on, for which I'm asking $5 USD. 
While I do feel a little guilty about charging for it. I feel more guilty
when my family has nothing to eat.

I think you'll find it's worth much more