Ah, this is a little bit embarrassing. I had somehow read your comment as meaning that somebody should make something like RubyMotion but with Smalltalk, with the REPL being a neat incentive. Rereading, I see that was totally in my head. Sorry. No idea what I was thinking, but it's too late to delete it now. I suppose my brain just saw "Smalltalk" and "iOS" in the same sentence and got worked up.

But incidentally, do you happen to know offhand of any resources about adding new compilers like you were talking about? That sounds pretty neat. I unfortunately missed the golden age of Smalltalk, so most of what I know comes from playing around with Squeak and GNU Smalltalk and reading about older implementations.