it certainly would be very nice. I explored this a little bit but on the end had to focus on stability of the core components. It wouldn't be anything too hard, but quite a lot of work to implement all the syntax quirks, keeping up with new commands, etc. So right now at least I personally don't have concrete plans to implement it. What you can do right now is use images from a local docker installation:

$ plash --from-docker busybox -- printf hi