WebKit.js: Yes it has finally happened Browser Inception is now possible.

In a way html2canvas[0] does actually do this, implementing a (minimal) rendering engine in JavaScript. I wonder how far this will go.

[0] http://html2canvas.hertzen.com/

Wouldn't something like this be doable with PhantomJS?

http://www.phantomjs.org/

Is there any reason you couldn’t actually do this with emscripten?