Have you considered sending copies of your DMCAs to google?
http://www.google.com/dmca.html
Read through the page, create the form, send it to the address.
The downside: the DMCA letters are published at
http://www.chillingeffects.org/ (
example).
The publication of those letters could provoke what is commonly known as the
Streisand effect.
Still, it is an effective way to remove your illegally shared content from google.