I have the same problem, I need to pack my Custom Theme in a single jar file.
this is a very usefull topic and I believe that will help a lot of people.
I think there should be a css generator for the skins we need like we have in jqueryui. That would be very helpful and nice. I think im going to try it hands on someday. . For now the best tutorial would be to see the book Practical Richfaces 2 and using their code posted on github.