https://github.com/schism-lang/schism
Previous discussion with comments by the author, https://news.ycombinator.com/item?id=16488605
Chez is a great Scheme, but it doesn't have a Wasm backend. I find https://github.com/schism-lang/schism very interesting.
As for C programs going crazy, well yeah. I did a thing where I would copy of the body of functions around in memory, it worked on some version of Linux and GCC, but only by accident. I would be much less comfortable doing this kind of circuit bending than modifying Python stack frames. If I were to achieve a similar goal in the future, I'd use TCC, generate C code and compile directly into memory.
Framehacks aren't going to do the same thing, and one should have tests for it regardless. Framehacks get you tail calls, stack scope and a bunch of other nice properties.
Happy Hacking!