While most everyone else has moved on to the land of 4 strokes, there's a group of intrepid engineers and builders in Australia devoted to the idea of building a 500cc 2 cylinder 2 stroke motorcycle, starting with the Aprilia RS250 chassis and installing their own highly engineered 2 stroke powerplant.
Grand Prix Engineer Wayne "Wobbly" Wright who has a 30 year career building GP engines and pipes went to work on the engine and the finished piece puts out 112 horsepower and 60 foot pounds of torque. Mounted in a bike weighing 286 pounds total and having the power delivery you would expect from a 2 stroke gives you a bike that one might call entertaining.
The idea here is to bring 2 stroke technology up to the best that can be built right now and place it in a modern frame and suspension package, a combination you can't buy in your neighborhood showroom.
The company the group formed is called the Two Stroke Shop, and besides many other parts for the 2 stroke fanatic, they offer not only complete RS 500 motorcycles but also the engines alone or kits to adapt your own RS250 to accept their engine.
There are no prices on the site, expensive I'm sure, but what they offer seems somewhat unique. It's an extremely interesting setup and just the thing to surprise the heck out of your average GSX-R pilot. I like it.
Link: The Two Stroke Shop