>FWIW, every contract I have ever signed has given the client rights to the source code. I believe this is a very crucial part of the relationship.

If you use any third party tools (frameworks, utilities, add-ons) in your apps, your license to use those tools probably states that you cannot redistribute their source code. So if this is the case, how do you separate your source code, which you want to give to your client, from their source code, which you can't release?