Implementing and using a Forth for a while for embedded real time scripting was a great in really re-enforcing how everything in programming really boils down to just numbers. Though practically speaking managing the stack gets old quickly.

If you look at Moore's forth style, he doesn't manage the stack, he just uses variables.

i didn't have practical exposure to Forth, only somewhat theoretical, but did to Postscript (yeah, that Adobe one under the PDF, printers etc).

Postscript is also RPN based..

And btw, the HP 11c "calculator" is also RPN based :) . Used it to solve some matrix things in university..

Have you tried RPL (reverse Polish Lisp)? It's on later HP calculators, and it's pretty elegant for a small-machine language. The type system includes matrices and functions.