The wireless projection keyboard isn't exactly new, and sadly the technology hasn't had mass adoption. With that said, Elecom isn't giving up, their latest TK-PBL042BK Wireless Projection Keyboard also has a "mouse mode" which acts like a virtual touchpad.
The TK-PBL042BK projects a red keyboard onto a flat surface and you type on that illuminated keyboard. A sensor on the projector will track your fingers and return the relevant key. This Elecom projection keyboard will work with iOS and Android gadgets as well as your PC via wireless Bluetooth. Not sure why you would want to use this with a computer however.
The Elecom TK-PBL042BK weighs only 77 grams, can handle 350 words per minute, has a "mouse mode", three brightness levels, and is quite expensive at $348.