I'm obviously coming very late to this thread and I've been dealing with the same issue since late last Aug.
@Uncle_DK what do you think may have been the factors that tied the sites together? Same IP, Whois info, analytics IDs, AdSense IDs, webmaster tools accounts, etc.?
We have been successful in getting one site out of the penalty. I'd be interested in whether anyone else has managed to recover any of the sites that were hit.