Jumping into the Ugly Mockup game. Couldn't hope for something looking good, but I was curious how the sizes would pan out. I assumed the 6.2 inch screen and little space above or below the screen stuff is true, which would mean not much more than 3 inches. Probably that is too little, but I wanted to err on that side. That being the case, I took a wiimote (a little over 6 inches) and halved its height but left the width the same. I further assumed it would have d-pad, analog, buttons. Largely because if it doesn't have both d-pad and buttons I think there are already perfectly decent mockups created days ago after the discussion about split d-pads equaling buttons, so redoing it but uglier would be pointless.
With the half size wiimote I moved over the d-pad and 1/2 buttons at original size, and completed the 1/2 into a diamond by rotating and overlapping with itself. Stuck the analog in the middle. Tried to scale it properly from a nunchuk, but it's hard to find an image of it facing forward next to a wiimote, so even uglier than the rest. Gave it two back buttons the size of the wiimote A button.
Pros: Both analog and d-pad are easily within thumb's reach in either orientation. Allows basically the same controls as original model 3DS. NES and SNES buttons intact. When paired all the buttons of a Dual Shock are available and then some. Used solo is recognizably a descendant of the wiimote.
Cons: Very small and cramped. But that's pretty inescapable if it's really not much more than 3" long? That's nearly 8Bitdo ZERO size. Keeping the design pretty flat as I did with the back buttons would be OK when it's all together, but not give a good grip when holding in one hand--more controllers flung into TVs like its 2006 this way. Also with all three of those elements (at full size) there's not much good place left for lesser things like -, +, Home, Share, power, lights.