So there was a really good post on parley, here it is. Lots of links to different research materials re: 'living off the rails' or whatever we're calling it :)
I've been playing with this idea too lately. Unfortunately can't spend too much time on it so I didn't get very far. There are however a few links that might help you:
These are related to Micah Martin's talk, "a sequel" to Uncle Bob's architecture one: https://github.com/slagyr/cleantracker https://github.com/slagyr/cleananalytics_rb
Some more projects that either try to implement this separation or are closly related: https://github.com/qertoip/guru_watch https://github.com/barsoom/devbook/tree/master/service_layer https://github.com/moonmaster9000/persistence_strategies https://github.com/bitlove/objectify#how-it-works
A bit of thought experiment of my own: https://github.com/elvanja/gedankenexperiment/tree/master/persistence_decoupling
But lately I've beed toying with: http://petelacey.tumblr.com/post/32626547077/making-uncle-bob-happy http://petelacey.tumblr.com/post/33090510132/use-cases And I must admit I really like this approach, almost as if Rails doesn't exist, I just wire it correctly and that's it. I am using this idea in a toy project, will put the code at github soon...
Also, http://obvious.retromocha.com/ was mentioned earlier in another thread. Haven't tried it but looks promising.
And some materials to read: http://silkandspinach.net/2012/07/06/hexagonal-rails-hiding-the-finders/ http://blog.mattwynne.net/2012/05/31/hexagonal-rails-objects-values-and-hexagons/ http://alistair.cockburn.us/Hexagonal+architecture http://jamesgolick.com/2010/3/14/crazy-heretical-and-awesome-the-way-i-write-rails-apps.html http://msdn.microsoft.com/en-us/magazine/dd569757.aspx http://victorsavkin.com/post/41016739721/building-rich-domain-models-in-rails-separating