I read some recent SQL blogs where the comments indicated at least a few people had put together DDL triggers and PowerShell scripts to extract changes from a database each night and check it into source control. Unfortunately I don't think I kept track of them and people hadn't published the scripts themselves.

If I was in your position, assuming the database structure was simple enough (i.e. not multiple databases referencing each other, < 1000 tables / procedures) I would probably investigate switching to the free SQL Server Data Tools; importing the existing structure or project, getting it up and running, and changing all of your developers over (depending on how many there are).

It provides an SSMS-style GUI interface to modifying tables and maintains the corresponding scripts itself, and full source control support. I'm also fairly certain it can also compare what's in the repository against the existing database structure to find people who have made unauthorized changes (though its intended purpose for that is to generate change-scripts for you to deploy).

The only problem is that this could be a lot of work, and some of the import scripts might need editing (i.e. SSDT doesn't like .. references with a .dbo. in between). There is also very little published documentation on using it in larger scenarios and managing the whole SDLC process... sure they tell you about generating a DACPAC... but I really need a more comprehensive workflow than that.