Joe Pagac's mural to the right of the (current) Cypress Hill mural (on the east wall at 318 E. Congress) is for Cage the Elephant on June 10th:
The shadows are from early-morning light.
Joe's website is joepagac.com.
Update (May 15, 2010): Today the Arizona Daily Star published a story about Joe's murals — including this one. It's This Tucson artist sees the big picture.