There was already a project to port emacs to run on guile. Guile supports both emacs lisp and scheme for this reason. The project seems to have run out of steam but it was mostly working at one point AFAIK.
Well, an Emacsen that hopes achieving the same degree of popularity as Emacs should be usable in Windows too. Last I checked, Guile had problems in Windows...
I wouldn’t consider running directly on Windows a hard requirement. You can run it under WSL[1|2] for instance, or bundle a very minimal WSL distribution that only runs your software.
