EDIT: Found this link in my notes as well: https://news.ycombinator.com/item?id=24900376
This looks like it has a smaller code footprint at least. I'm not sure RISC-V is a very good target for this sort of thing. E.g. decoding the immediates in software is going to be very slow, whereas in hardware it's fast.
But on the other hand it is a stable target and can be configured to be a lot simpler than WASM.