I read this article on WWDC on 9to5mac and near the bottom in the different scenarios, it's possible they say a new iMac isn't even in the books?
http://9to5mac.com/2012/06/08/wwdc-...-MacAllDay+(9+to+5+Mac+-+Apple+Intelligence%2
http://9to5mac.com/2012/06/08/wwdc-...-MacAllDay+(9+to+5+Mac+-+Apple+Intelligence%2