I'm not sure whether or not this is the right place to post suggestions for upcoming ReSharper versions - please point me to the right place if I'm wrong :)
ReSharper itself is the most awesome tool and extension I've seen and brings a lot of improvements to the .NET world.
What I'd love to see integrated in ReSharper is the ability to extract methods to an already existing interface (and implement it if not already). The current "Extract Interface" method does not allow to choose an already existing Interface-name so the selected methods get appended/implemented to that interface, instead it'll create a new interface with the same name and implement it, which obviously causes errors.
Would love to hear some feedback and whether it's possible to intergrate that or not.