A little reaserch on LLVM has revealed that among the front ends available is on that uses Java bytecode and compiles to LLVM bitcode. It is thus possible for PNaCl in the future to support applications written in Java without requiring a separate interpreter. Additionally there are front ends for many languages including C/C++.

This is a fantastic target for universal code. PNaCl is not native, but with aggressive optimization it can run with the near efficiency of native code, but in a language, operating system, and architechture independent way.

I'm surprised LLVM isn't at the center of more OSS projects.