Alpha-Novatech, a large supplier of forged heat sinks, has made their products available for download in HeatSinkDesigner format.
HeatSinkDesigner is thermal software focused on finding the optimal heat sink for a particular application. It will rapidly optimize a custom heat sink design or find the best available off-the-shelf heat sink. A free trial can be found at http://www.heatsinkdesigner.com/id56.htm#download
Alpha-Novatech's heat sink library can be downloaded at http://www.alphanovatech.com/ref_datae.html