Snes9x on the PC is mostly coded in C for compatibility isn't it?
I managed to get ZSNESw working at just about full speed on my old K6-500 machine. The DOS version was much quicker, but I had no sound coming out of it.
by native do you mean amigas without accelerators? Just about all of the 8bit console emulators I've had over the years run at full speed on my machine, even Wzonka-Lad ran at full speed on fast and inaccurate settings.