I have successfully converted the XNA 3.1 Real-Time Reflection example to XNA 4.0. You can find the XNA 3.1 original example from the XNA Community Website. This example of real-time reflection was originally created by Canton Javier Ferroro. The reflection of the ship is distorted by the shape of the wood. The technique used is based on making a render with a reflection angle using a clip plane and saving this into a texture for use in the rendering of the scene. This technique is similar to games such as NBA 2K8. I have made the source code available here.