Compiling a Win8 application from a Win8 Metro application (and possibly running it in a sandbox)

I have a slightly strange question. Is it possible for CodeDom or Emit to compile a Win8 Metro application (.NET or HTML5 / JS) from a Win8 Metro application and then run it (do not install it, just run it until the user closes it / stops it)? I think this is a kind of need for MEF-ish.

I could not find references to this need. I tried to get through what Rosetta strong> is / does, but not very far from understanding how much better / differs from CodeDom or Emit, and if that was even what I'm looking for.