Your post got me to purse some of my own ideas about about deploying Python applications. I've written a small script, whisk, that (ab)uses setuptools to build a working envrionment for deployment.
You run whisk HelloWorld GoodByeWorld and get a working environment that contains HelloWorld and GoodByeWorld, their scripts, and all of their requirements. easy_install does the installation, so the arguments can be files, URIs, and requirements. The resulting scripts automatically find their envrionment's libraries based on the value of sys.path. This is more along the lines of OSX Application bundles and CRL Assemblies than what you're talking about, but I thought it might give you some ideas.