Yeah, the wm didn't look that great by modern standards. However, the whole underlying idea is pretty compelling. I'd like to see something like plan9 or inferno retrofitted with a more modern interface, loaded with modern tools and, yes, being built around a more modern language.
I've been messing around with Inferno for a while (link below for completeness). I would love to have, say, Clojure, Python or something else with a sizable set of built-in libraries running on it, but (at least where Inferno is concerned) I had a lot of trouble finding anything to bootstrap that kind of environment (Inferno uses the `dis` VM, and there is a GSOC project that sort of gets Java running around that, but, again, no readily usable stuff).
Nonetheless, I might try a vm of plan9, for fun.