Doesnt' Surly make one? I think others do, too.
Adding mounts isn't all that hard if you have a welder--I did it here
http://www.endless-sphere.com/forums/viewtopic.php?p=551029#p551029
http://www.endless-sphere.com/forums/viewtopic.php?p=551150#p551150
by cutting them off another fork and welding them to my Suntour forks. I didn't do it quite perfectly, though, as I was not that careful lining stuff up apparently. Could be done easily enough, if one is paying attention.