Rumor has it that Apple has a tablet computer with a touch sensistive screen in the works. This is very interesting to me because it could simplify creating user interfaces in software for virtual instruments which present their tonal options in terms of harmonics, rather than force-fit to the equal-tempered scale. It might even be possible to create a usable performance instrument within the constraits of such a device, without having to migrate it to a larger display or custom-built gadget. I certainly intend to try.
Meanwhile, you can learn more about harmonic-based music at the wesite of The Just Intonation Network.