Recently I bought a Raspberry Pi Zero, partly because they only cost a fiver and partly because they're tiny enough to make into cool gizmos like this. http://www.8bcraft.com/
Although not as powerful as a Pi3, the plucky Pi Zero seems quite happy emulating 16-bit generation games like Super Mario Bros on the SNES and so I'm lead to imagine the Dragon is well within it's budget capabilities??
In theory it should be easy to test. The RetroPie distro I'm using incorporates XRoar albeit it's not installed by default. And this is where my master plan unravels. When I attempt to install XRoar using RetroPie's `Package Manager' it throws an error which I'm too stupid to understand.
That was a very confusing error message given the nature of the problem. It didn't help that there's a space missing between the repo name 'xroar.git' and the clone destination '/home/pi...'. Plus still no idea what error 128 is. Not obvious to those of us that don't wish to rtfm and use git gui instead
I should think that the performance is very similar to my laptop. i.e. more than plenty for the job.
A user on the RetroPie forum was able to point me in the right direction and after that it was a piece of cake!
Also, once the Pi's part of your wireless network you can drag 'n drop games/roms onto it's MicroSD card via your PC, then reboot the Pi, select a game from the menu and you're away. No need to type anything.
Performance-wise the Dragon and CoCo games I've tested are perfectly playable. I've also tested `Super Mario World' for the 16-bit SNES which was also fine. Maybe if compared side-by-side with a Pi3 running RetroPie you would see a small difference in performance? Maybe not?
Anyway, my next step is to take advantage of the Pi Zero's diminutive size and low power consumption by hooking it up to a 3.5" LCD screen and battery, and building it into a pocket sized case. Adafruit have a few nice examples but my current favourite is the Raspiboy kit by http://www.8bcraft.com/