Here is the StormC project including assembly language optimized code for m68k...please note that this version is outdated, I'm currently rewriting a lot of parts in order to make porting less painful. This version compiles only on Amiga right now and works very fine with the UAE emulator:
TuComposer 1.0 pre-ALPHA Source Code (Zipped)
TuComposer 1.0 pre-ALPHA Source Code (Aminet compatible LHA-Archive)

BTW: License will be GPL...