I have successfully converted the XNA 3.1 Real-Time Reflection example from the XNA Community website to XNA 4.0 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 my source code for the XNA 4.0 version available below.
XNA 4.0: Download
Indie DB Page: Download