I really like the direction you're going with PluriBASIC. I know the concept is solid because I'm already enjoying O2 magic in DLLC.
I don't know of any scripting languages that can call API functions with dynamic on-the-fly FFI definitions, call virtual DLL functions from a string of O2 code and access / create most C structures and variable types.
I don't want to make you cry talking about DLLC's low level COM functionality.
Best part, one include.