There has been an artist at Star Wars Celebration V who has been working on this giant street-art-sized piece since we arrived. Well, I'm sure he took a break here and there, but the image above is almost complete and now reveals Darth Maul's brother "Savage Oppress." I'm not sure if I am spelling that right.
UPDATE: The artist that has been working on the chalk art mural at CV is Eric Maruscak. He has a website at www.pepperink.com and has a Facebook page about his artwork right here.
UPDATE #2: Check out some screencaps of Savage Oppress from the TCW S3 trailer as provided by our good friend Paul Bateman.