It is not exactly sold as one "kit" . You do want to stay with same brand. Moen and Delta are two good brands. If you go with the "designer" brands that you will see at design showrooms, then future parts availability is in question.
Go to a good plummbing supplier. They will have catalogs, and the catalogs show what goes with what, and show you the style and finish choices. You can also see these the K/B desk at HD, but the problem is finding someone who knows anything. The manufacturer's catalogs are pretty good at showing you what trim goes with what valve, and even have diagrams for the mutihead/diverter valve setups. It is not rocekt science if you pay attention. I have seen people order stuff from the depot where A did not work with B.