It's worth noting that the part number (TM4*) indicates it's not part of the Stellaris line (LM4*). I wonder if this will be part of the Hercules "safety microcontroller" family, possibly replacing the Cortex-M3-based TMS470M family?
Still a mystery, I'm guessing they are replacing the whole Stellaris LM4xxx lines with new line and new name "Tiva" ?

The reason is I spotted its mentioned in the latest April 2013 Stellaris
LM4F120H5QR Rev A1/A3/B0 Errata document (
Here), attached the interesting screen shot below.
Also looking at the board layout, its almost identical with the Stellaris Launchpad.