Well, fwiw, the binary that does exist (which does, as far as i can tell, parsing, type inference/type checking and a bunch of semantics checking, plus it walks to AST to generate code (except it doesn't actually generate code yet), so far is insanely fast, even in verbose mode (where it prints a load of shit to stdout).

As for proof of concepts, on the mailing list he has stated that ANI is more or less a natural progression from previous unreleased projects.

Having said that, I agree that focusing on getting something working before trying to make it fast is the correct way to do it...