I've tried the Moebius workaround (see above). It seems to work, and
. . .
seems to call my MIT scheme and do results just fine. But it ignores the idea of multiple sessions, which the geiser-based ob-scheme did so well and just has one MIT scheme "session." However it does not start a normal scheme REPL, rather, a "scratch"-like buffer that, in fact, seems to have MIT scheme listening to it. That is, I can type in
(define (me x)
(* x x x x))
and with C-x C-e everything is working, just like scratch and elisp do.
Will try to use your patch and get back to you