The V8 API seems to change quite often. Node.js has the resources to track it, and NAN abstracts the different versions behind a single API.

I wrote nbind on top of Node.js and NAN, with similar objectives as vu8, but also targeting Asm.js and later mobile platforms with various engines, so it's already independent of any specific JavaScript engine. It has survived one v8 API change so far. Bindings are automatically generated using templates and the C++ code only needs to deal with normal C++ types.

If you still have a need for this kind of binding library, it would be good to collaborate. There are many similar projects, although I'm not aware of any other than mine that wouldn't be dead at the moment.