Andy,

Why not treat database code in the same manner that application source code is treated and work from a real version control system? We are using Visual Studio 2003 and although I'm not particularly fond of the editor, it allows us to set up database projects and have all source code in VSS. I had one of our developers create a Visual Studio add-in that creates a database build script from the source files in a project. It is working out very well thus far.