This is seriously awesome! A real banger! It was actually around the time I wanted to start making pixelart but had no comfortable way that this came to my attention! I'm gonna be using my dsi xl with my dspico flashcart!
On that subject, the dspico supports dsi features like the better processor and pictures and the other many enhancements, I was wondering if in the future development of this if dsi features will be used.
I think a really cool example of dsi's chips being used in a non game is Korg ds-10 has double the tracks, synth power and many other things, the entire thing worked on DS but for features like just to have more of what already was there they used the dsi wich is really cool, usual flahscarts don't really work with dsi features but dspico does also that's why it could be useful and interesting!
Either way this is already insanely cool, hope to see future development of this and that you achieve being able to have more than 128x128 pixel frames like you said you plan to on GitHub!