What's happening now?
We all carry cel phones that are also personal computers, MP3 players, and gaming machines. They're made by Apple, Microsoft, and Google (which started as a search engine, like Lycos. Kurzweil and Berners-Lee work there now.) Apple's and Google's run 'nix. Apple's and Microsoft's are pretty hi-fi miniatures of their respective flagship OSes - in fact, in Microsoft's case, things flipped upside down and the phone UI design started driving the desktop.
TL;DR: Pocket PCs. Unix, Linux, "Windows"