Check out http://www.worldofballpythons.com - they have a section with all the morphs listed, and it shows what the genetics of each are (for example, if you look up a Spinner, it says that the genetics are Spider and Pinstripe). That's the only site that I know of that's close to what you're looking for, but I'm curious to see other sites out there. It would be nice to have a site that generates "what do I get if I cross a X to a Y" with percentages and all.