jimbeetle - 3:30 pm on Mar 13, 2013 (gmt 0)
One thing you haven't mentioned is traffic. Has the rankings drop you see affected the site's traffic?
And I find this a bit prolematic:
Have you checked to see if any backlinks changed to nofollow?
YES no changes - I own the most sites
I assume that means you own most of the sites that link to the affected site. If so, Google might have just caught up to your link scheme and given you a bit of a slap.