The CLARM.exe thing you see is not a driver, it's the actual compiler.
CL.exe is a front end that dispatch actual compilation to CLARM.exe.
I don't have EVC installed here to double check this... But if you look at VC6, you have:
CL.exe (50k) --> what you call
C1.dll (667k) --> "C" front end
C1XX.dll (1179k) --> "C++" front end
C2.DLL (837k) --> back end
MS is not going to release a PPC SDK for EVC4... There is no point (for them) in doing so.