I'm interested too!
I'm really a C programmer and I don't like GUIs too much, but I'd really love to have a better user interface and I'm (slowly) trying to learn a bit of C++ and Qt.
IMHO right now the worst problem is that there is way too much refreshing in the wrong spots, that makes the whole thing feel kind of sluggish. While some lag is unavoidable because of the way e-ink works, it can be way, way better with a clever design (Sony did a good work with their devices, I think).
To give a try to such sort of things does not depend on having much more than the current SDK, but to design the whole system_manager again from scratch is another story, because it manages a few different things like proxying eink refresh requests, keeping track of usb status etc. I haven't looked at OpenBOOX, so I don't know how this was handled (original system_manager with a brand new gui_shell?).
It would be very nice if we could all agree on what should be the "project" goals, what should be done first and so on... looking forward to this!