In some hosting companies that support Node.js (like Nodejitsu and Heroku) you can deploy your static files as part of your application code. In other words, when you deploy your app both your code and static files (JS/CSS/Images) will be deployed.
The downside with this approach is that you cannot easily just change a CSS file like you can in a more traditional deployment where you can just FTP a new CSS file to the production server. You could bypass this if you host your CSS files somewhere else, though.
I don't have experience with AppFog but I suspect the same is true.