According to this Technology Review article, researchers in Germany have developed a "radically reconfigurable" satellite that can change missions on the fly.
The researchers, led by Toshinori Kuwahara of the Institute of Space Systems at the University of Stuttgart, plan to launch a test satellite called Flying Laptop in 2012. The spacecraft's onboard computer will be able to reconfigure its own electronic hardware. The satellite will also carry a suite of instruments and sensors including cameras, multispectral imagers, thermal infrared imagers, and GPS receivers. The research appears in the spaceflight journal Acta Astronautica.
The technology could lead to the sharing or re-purposing of spacecraft. The abstract is here.