Not entirely sure I see the point. I would like to see Emacs/Guile. Emacs need a more modern elisp (or in this case, Scheme) implementation. It's much easier to make it compatible with the mountain of existing (and useful!) elisp code if you are also in a form of Lisp. That's still not trivial. It also needs a better front-end renderer, across platforms. I could understand if the "NG" part were to be just about that.…
It doesn't make sen to have multiple interpreters jury-rigged up (the horror!) And it also doesn't make sense to throw away all the lisp by having no interpreter for emacs lisp. Guile does support emacs lisp just for this purpose.