There are a few ghost bikes in the Cincinnati area. I often ride past the one set up near Lunken Airport for Andrew Gast, where some nice improvements have recently been made to the adjacent trail/MUP. I saw one in downtown Pittsburgh during a trip I took a few months ago, as well. I think it's a fairly common practice (at least in the U.S.) wherever there is a vibrant cycling community, and wherever unfortunate incidents lead to the loss of life.