Recently I let you in on Chris Carpenter's Google Cash Detective at http://www.GoogleCashDetectiveV2.com
I hope you got a chance to join, if that's the kind of business you're in. It's not cheap, but WOW is it worth it. I've been using GCD myself for the last several weeks and am constantly amazed at the information it can extract from other people's Google accounts.
It's spooky. (And profitable.)