According to TSA's website, the backscatter machines are gone...period...

From blog.tsa.gov:

"All Rapiscan AIT units currently operational at checkpoints around the country, as well as those stored at the TSA Logistics Center, will be removed by Rapiscan at their expense and stored until they can be redeployed to other mission priorities within the government. Most of the backscatter units being removed will be replaced with millimeter wave units. The millimeter units will be moved from the inventory currently deployed at other airports and from an upcoming purchase of additional millimeter wave units.

By June 1, 2013 travelers will only see machines which have ATR that allow for faster throughput. This means faster lanes for the traveler and enhanced security."