As you said, it isn't much, but this is actually pretty nice output, especially from a new user!
As Jeremysr said, it is possible to combine all your sprites' colorsets to make one palette work for them all. However, you WILL have to load it twice (once for bottom screen {Sprite.LoadPalette(0,0,"allpal.pal")} and once for the top {Sprite.LoadPalette(1,1,"allpal.pal")}.)
Additionally, SOME sprites (mostly only sprites you convert directly from GIFs) use 'special palettes'. Those will probably NOT work with my method. However, the only time I've ever seen one is when I convert directly from a GIF. Other than that, there aren't very many exceptions, if any...
And glad that you liked DSLua. To be totally honest, before I started it, I thought DS homebrew was *crap*. But this was the easy push I needed, and soon C++ became easier and easier, until I learned PALib entirely. I am now learning the entire dev package (devkitPRO!), and wouldn't be if I didn't have this easy start...
Err, anyway, if you're worried about how slow this runs... know that I have tested it on 2 different compatible carts and it runs full-speed
