I picked up these two Pippin controllers from auctions in Japan thanks to a friend there. They arrived in today. The black one is an @world one (from the US Pippin). The other one is a wireless Japanese Atmark one. This one also came with the vital ADB adapter I needed to connect the @world one (you can see it in the middle).

The wireless one takes 4xAAA batteries (2 in each handgrip).

My first aim is to see if I can somehow configure Descent (or Descent II) to use them. Controlling the ship with the trackball would be awesome! There's an InputSprocket driver for them but I don't think either game supported that.