I wouldn't want to write using C as I prefer coding in assembly, you wouldn't happen to know of an assembly compiler for writing in PPC would you... 
Maybe you could have a look at
ECX. It is a follow up of the
AmigaE with support for PPC. It has support for inline PPC and M68K asm so everything but the function headers could be in asm.
You may even like the language as it is kind of asm like language (mostly not typechecked) with a nice syntax that even allows object oriented programming but still with a low level feel.
greets,
Staf.
