Couldn't you replace v8 with this and recompile the node binary? If it passes 100% ECMAScript tests, that should mean it's a drop-in replacement for v8. Correct me if I'm wrong.
fs/net and some other important pieces of Node.js are written as C++ addons for v8, hooking them would be very difficult I guess. Though Microsoft have been working on this for their ChakraCore engine. There was a conflict if I recall correctly, Microsoft suggested to add another abstraction layer to make hooking other JS engines easier but Node.js team refused it. I might not know that situation very well. But I have downloaded ChakraCore based Node.js once and it ran my project without problems, though the performance was about 5% slower.
Some Node APIs could probably be implemented using the std and os modules[1], but others (e.g. networking) would probably need to be implemented via the C API[2].
