This sounds doable. The compiler already contains code to do vector operations using MMX, i.e. the code to multiply arrays is there. This can be reused for such a port.

The PS2 uses a MIPS processor, but the compiler has no MIPS code generator yet. It should be straightforward to implement one. The MIPS is a very regular processor so should generally be easy, the only obstacle might be the lack of flags.

Basically all that is needed is someone with plenty of spare time