Nanite seems to be laying the foundation for something similar to Heroku.
http://brainspl.at/articles/2008/10/11/merbcamp-keynote-and-introducing-nanite
http://github.com/ezmobius/nanite/blob/b9f5af0569abf25c43602ade51c1da2964fa98e1/README.rdoc
http://brainspl.at/articles/2008/10/11/merbcamp-keynote-and-introducing-nanite
http://github.com/ezmobius/nanite/blob/b9f5af0569abf25c43602ade51c1da2964fa98e1/README.rdoc