I've been looking at Unity 3D for developing a 3D PC game and I really like the scene editor and how it simplifies the process of constructing 3D scenes, managing assets, animations, transitions etc. However, I don't want to restrict myself to using the Unity 3D scripts for handling every bit of game logic in the game.

E.g. If I want to construct a RPG dialogue system I don't want to do it with unity 3d scripts - I'd like to use C#/.net. Also, I might want to use e.g. windows azure and sql azure as backend, and use 3rd party .net libraries such as reactive-extensions etc.

Is there a .net engine out there that helps me with asset loading, animations, physics, transitions, etc. with a scene editor, but allow me to plug it into a visual studio .net project?

Thanks