I have often wondered what it would be like to have an "all-levels" Lisp-like language. Start with a bootstrapping reader that attaches to a minimal assembler that generates bytecode from the S-expressions. Then build progressively higher levels onto that until you have a "proper" lisp system, except you can drop to a lower level anytime and hack the depths of it when you need to.
Have you ever looked at Forth? It's postfix and stack-based, but is exactly what you want from the standpoint of bootstrapping from next-to-nothing and getting a high-level language.
