For a literal definition of promising Kickstarter is busy seperating fools from their money, most seem to falter at moving past the concept video stage though. Tap apparently nearly works: https://www.theverge.com/circuitbreaker/2018/3/8/17096786/ta...

Of course one of the big problems is that our portable monitors still need at least one of our finite set of hands, so it seems like we'll need AR/VR monitors before they become practical. But then if we have the free hands something more like a traditional keyboard would probably work.