We think it's likely that they went through the same sort of evaluation process that put the Secure 1000 into service, and that they should be publicly reviewed by independent researchers.
From L3's sales site for the ProVision MMW machine, sample images:
http://storage.pardot.com/16582/23361/product_provision_L_3_...
Their "ATD" model that includes image analysis to automatically flag "anomalies" only seems to show front and back, too.
http://storage.pardot.com/16582/23381/products_ait_ProVision...
In 2012, the "TSA Out Of Our Pants" guy previously documented the "conceal a metal object on the side of your body" attack, and did so against the MMW machines with the ATD software on them:
http://tsaoutofourpants.wordpress.com/2012/03/06/1b-of-nude-...
It's too bad the "TSA Out Of Our Pants" guy didn't have a hidden camera accomplice to film his entire trip through security.