There was a Pacer, Tripacer, or Colt advertised a while back which was a biplane. But it also had flaps on the lower wing, so wasn't just extra wings bolted on. Most of us were curious how much the drag was affected with the extra wings and struts? And, it sure looked like a real pain getting into, and out of. But it was an eye catcher.
I wonder if it ever got sold? It was listed for a long time.
