I would pay a lot for a Rails-like framework written in Erlang. Erlang really hits a sweet spot between performance and developer-friendliness.
I played with it and found it to be pretty Rails-like, even including several moments of "what foul sorcery is this?"
Check out ChicagoBoss, another Erlang web framework which claims to follow the Rails-like MVC pattern closely.
Chicago Boss can't compete with all the users and plugins and everything that Rails has, head on, so it's probably best used where it has an advantage on Rails: stuff like websockets where holding a lot of them open is a piece of cake for Erlang, but more of a resource hog for Rails (at least it used to be that way, has 4 improved things?).