According to InnerBits, Sony has been working on a SIXAXIS controller with rumble support for a few months now, but are having difficulties with battery life. Between the rumble and the wireless support, the batteries are draining too fast to be acceptable for consumers. Officially, the company has kept a tight lid on things until the issues are resolved. Incidentally, there was no mention of the rumble having an adverse affect on the motion sensitivity.
As usual, there was no mention of a release date for the controller and it is still unclear whether Sony will make the new SIXAXIS controller the default option for new PlayStation 3s. A financially expensive, but positive PR move would be to offer all current consumers the opportunity to “upgrade” their controllers for free.