That would be great. You should work with the Chakra guys. I've created a engine agnostic API for C++ here: https://github.com/CauldronDevelopmentLLC/cbang/tree/master/... It currently works with v8 and Chakra.

One of the key advantages of my API is that by using a "sink" interface it can be very efficient because the implementation calls the engine's API directly with out creating intermediate data. As I mentioned this is in C++ but it could easily be translated into a C API.

Let me know if you would like help with this.