> and so imagine if you could emulate some platform at high performance with low overhead, in a sandbox. You would then be able to script in whatever language you so desire, provided it has that target.

My understanding is that this is what Google's PNaCl was about (https://developer.chrome.com/native-client/nacl-and-pnacl) : leveraging LLVM bitcode for both portability (source and target) and native performance, being able to sandbox properly the resulting executable.