I think the challenge would be not in the air frame or rotating motors...but in the software. How would you setup the radio so that rotating the motors changes the control surfaces that are moved? Even the much more complex multi rotor things still maintain a single direction. But you would need something that with the flip of a switch the motors would rotate and the orientation of the sticks to the control surfaces would also change. Tricky!
Even tho small scale models have advantages over full scale, it would still be cool to have a long wing, slow-fly for take off and landing...and then a short wingspan for high speed flight.