The crew has also designed their own patch, which is also very unique, and utilizes a virtually universal emblem of Rescue.
Since the STS-400 mission itself is a bit of an "underground" effort, being done in a minimalist way, NASA has not given the crew any official support for such an emblem.
Please note that these are UNOFFICIAL.
(Thanks to nasaspaceflight.com for the info and images.)
Left and middle: the STS-400 designs embroidered as 10 cm patches by Starflight Creations; right: the 9 cm version available through The Space Store, manufacturer unknown.