I got myself a DNA Sonett recently so have to let my Concerto go. It was bought direct from Dr. Meier last June and it's in absolute mint condition.
It's black in color (not produced anymore, according to Meier himself). I am asking $SOLD including PayPal fees and shipping to the US.
My old feedback thread: http://www.head-fi.org/forum/thread/464789/pekingduck