Google App Engine for Node.js/Javascript?

Check out AppengineJS. It isn't Node.js based, but it is a port for the Python SDK to RingoJS (and a little legacy from another libraries).

Very promising!

Check out the Caja project. It uses JavaScript and is being adopted by Google.

I built a simple open-source framework to let people develop JavaScript web-apps on Google App Engine: https://github.com/lmatteis/apejs/

It runs on Java (Rhino) and it hides the entire Java layer from you so all you have to worry about is writing JavaScript code.

I hope the Moderators won't consider this spam since I wrote the software, but it's open-source so I shouldn't get any weird message from them.

I think the point is that during development, Google programmers like to use tools like Eclipse that use static typing to allow sound refactoring and easy code navigation.

And although V8 is impressive, Java still offers generally better performance and features such as low level access to e.g. memory mapped files, binary network protocols, etc.