I've submitted a patch here to let :layout work with the :file option when rendering in a view... http://dev.rubyonrails.org/ticket/10944
I've re-prioritized the rendering for the passed in options in order to allow a :file to work with :layout. The fix is easy, but the explanation is a bit complicated.
Can someone take a look and let me know if this fix looks correct or if another approach should be taken altogether? I also don't know where to include tests for this, so if anybody can point me in the right direction, I'll add the tests.