Its going to be an emulator regardless of who makes it. Nobody is going to start making HuC6280s just for this thing.
As for the aspect ratio; while I'm sure it's easier to source a wide screen, if you are a real company you'll find that you can actually get screens made for you specifically. This is how every decent piece of gear gets made, the iPhone, the 3DS, the Vita, etc. These companies aren't dumpster diving for EOLed mobile phone displays.
I recently bought a TASCAM DPS24SD. It has a pretty square screen, although the constrast is below the current state of the art by quite a bit. There are thousands of LCDs to chose from these days.