There was a leak for Roberts about one hour before his July 19th announcement. So this Miers thing may be for real. After all, if no other nominee has arrived at the White House gate, then the nominee must be someone that works inside. I'm sure there are people watching where these people are physically located.
Miers donated to Lloyd Bentsen in 1987, and Al Gore and the DNC in 1988. Since then, all GOP.
http://www.newsmeat.com/washington_political_donations/Harriet_Miers.php