If my fabrication and coding skills were up to it I'd be doing a whole control panel display for the motorcycle.
One of my long term projects is exactly this. The goal is to replace the entire wiring loom (except the engine management) with a couple of Arduinos to control all lights and monitor and log the state of the brakes, engine, suspension etc. There will also be a graphical LCD displaying some of this data, it will probably not replace the current speedo/tacho though. I have prototyped large portions of this project, but so far I haven't done anything on the bike. That will have to wait atleast until next winter.