I wonder if the creator of this thread even knows how "fast" nulldc goes on PSP:
Dreamcast emulation is not suitable for Raspi, beyond "proof of concept" app, same as for PSP nulldc.
drkllRaziel, author of nulldc, started a sideproject called nulldce focus on low powered systems and supporting arm devices, but peeking at its googlecode site it seems to be a bit dead. If I'm not wrong those videos running dreamcast on PSP are showing some work of drkllRaziel himself.
It will be a coding miracle if the thingie reach to show a playable framerate for early N64 games (without some critical overclocking at least). I think that could be the ceiling for Raspi emulation and honestly I don't count on that to happen.