I recently looked at some other posts relating to this topic but as far as I can tell there is currently not a working plugin or script for QGIS 2.0 to achieve a four color theorem for styling polygon vector data (it doesn't necessarily have to be 4 colors, just so that each neighboring polygon is a different color, though keeping it at a minimum number of 4-6 colors would be elegant). I will ultimately be displaying my data using Leaflet JS, so if there is a plug-in for Leaflet to accomplish the same that would work as well. If anyone has a working script or plugin to share I would appreciate it, thanks!