I dunno. The market for something along these lines is probably as big as a substantial portion of the entire portable computer market was in, say, the late 90s. And it'd have basically no competition (at least at launch). Seems like it should be a viable product that could be brought to market at a non-insane price. Should.

Capitalism's weird. We end up with the most popular version of a thing being dirt cheap and common as air, and anything even slightly different or better being impossible to get or absurdly expensive.