I've always kind of wondered if it would be possible to constantly emulate a stylus held somewhere on the touchscreen and offset it to match the circle pad, specifically for SM64DS. Were it even possible it would be quite a project, but it would be cool.
That being said, it seems rather unlikely. I understand that 3DS hardware is turned off in NTR/TWL mode, so there would be nothing around that knows how to read from the circle pad. The firmware we're working from doesn't even know what a circle pad is. Yes, we can break into TWL and get its hardware working, but breaking into CTR would be a hell of a trick.
The only thing that makes me think it could be possible is the fact that it's used for d-pad emulation. If we know what does that we could maybe mess with it. But I dunno.