C#/.NET (WPF) Game Engine

I am looking for a developer rewrite or expand the rendering portion of a game engine I've written in C# and .NET (WPF) for the Windows platform. The engine currently provides basic rendering features written on top of the WPF canvas, but this has limited capabilities and poor performance (in my implementation anyway.) The scope of work is to improve performance and facilitate animations. If you are familiar with an engine (such as SDL) that can be used and embedded and integrated into a WPF application then that would be great. Depending on the quality of work, and if desired, this may turn into a more general role of working on this project with me with additional compensation. Meetings for progress updates and coordination will take place either early morning (8AM EST) or at night (8PM EST) depending on candidate's preference. The delivered product should be extensible that allows other developers to build on top of its foundation. This project is geared towards creating a versatile and robust game engine, so the successful applicant should demonstrate their knowledge of game engines, as well as their understanding of what will be necessary to develop a compelling engine. I intend to customize this framework in the future, so the developer must have an understanding of what will be necessary to extend the scope of the game engine. Any questions or discussions concerning the scope of this project are welcome and appreciated.