>>1
What's so funny? The original C++ compiler was a C++ to C translator. That's all compilers are anyway, pattern matchers which transform a bunch of structured input patterns into structured output patterns. Doesn't matter if the output is another high-level language, intermediate representation, or machine language.
Using cfront is the least amount of work to get C++ support. They could port clang/llvm, but they would need to do a lot of work in the llvm backend to support Plan 9.