[casenelson]

Working against Rails, or any framework, is definitely going to cause pain. On the other hand, Rails is not perfect and I, like the OP, have been noticing a number of voices lately worrying about building large Rails apps. Which is awesome, because either Rails will adapt or something new will come along to fill the need.

Sinatra + cherry picking rails lib might work great if you've built a few apps like that, but it would nice to package this approach in a framework which guides people down this road.

Personally, I feel that Rails could evolve to the point where the approved path involves using some adapter (like a service layer) to talk to ActiveRecord. I've written about how Java accomplishes this in comparison to ActiveRecord: http://casestatement.tumblr.com/post/11514731433/javas-jpa-f...

[generalk]

  > Working against Rails, or any framework, is definitely 
  > going to cause pain.

There is a huge difference between working "against" a framework and working outside, or better yet alongside of it.

You want a Service layer that abstracts logic from database commands? You can absolutely do that while still taking advantage of the entirety of Rails. Your controllers and views are instantiating your objects and not ActiveRecord objects, but that's not a crime.