Now that is cool. Too bad that it never got enough crowd-funding. Someone else is working on a similar project
https://www.youtube.com/watch?v=DimKzODY-n4http://www.pianodevoyage.com/X-Key Air - I didn't care for it at all. Stylish, and full size keys, but I'd rather play mini keys with more depth. The Korg Microkeys are very playable, much cheaper than the X-Key. Also, the X-key doesn't provide a Windows BLE driver whereas Korg does.
If anyone wants to carry a grand piano, here is one.
https://www.youtube.com/watch?v=DimKzODY-n4