Come to think of it, I haven't seen any multiband images of the famous "dark streaks" either. I found some single band images after a web search but no multiband images:

Arabia Terra (Released 16 October 2002)
"This image shows deposits in a crater located in Arabia Terra. Arabia is generally dust covered and dark streaks or dust avalanches are present in the crater walls. The dominant geologic process acting in this crater interior is wind erosion. The central crater deposits are eroded to form yardangs, or linear wind-sculpted hills that resemble an inverted boat hull. Deflation and abrasion are capable of eroding rock structures that are aligned parallel to wind direction. In the lower right hand side of the crater, a dark deposit has formed barchan dunes. These crescent shaped dunes have 'horns' that point downwind indicating general northwest to southeast wind direction. These dark sands probably played a role in the erosion and formation of the yardangs."
http://themis.asu.edu/zoom-20021016a.html

Bob Clark