For starters, you are going to need a new name. Luna has already been used multiple times for language projects.
The point of this additional syntax of sexp (another horrible name) completely escapes me. If you want to do some sort of internal translation, fine. But having more than one syntax exposed to the user is a recepie for fail.
So this is basically Lisp/Scheme with static typing? I don't mean to be negative, but I don't see how this is going to appeal to C-family programmers. They are going to find a much more attractive package in the functional extensions to existing C-family languages, and the static-typed functional capability in F#. It seems your real target is traditional functional programmers looking for better performance.
Well, have fun with it. Maybe it will turn into the next big thing.