As far as ergonomics go, a controller-like form-factor is almost definitely the current ideal for a portable, carry-able, holdable keyboard. Obviously just slapping QWERTY on it wholesale may not be the best idea, and doing the R&D for a more appropriate layout or entirely different approach to input could be costly. carriers for phones or other devices could also complicate it. Might be the reason there aren't more on the market?
Is there anything like it out there now? I searched around for something like this a while back, wasn't really satisfied with my findings, and haven't been able to stop thinking about it since.
