I've decided to spend a day or two polishing my Uxn/Varvara implementation for NDS - added a native 3DS port, as well as a new, suitable keyboard design; both are debuting in today's 0.4.0 release. I think it's feature-complete now...
https://github.com/asiekierka/uxnds/releases/tag/v0.4.0
Immediately followed by some fixes.
https://github.com/asiekierka/uxnds/releases/tag/v0.4.1