Red Gate's SQL Compare product not only allows you to do object-level comparisons, and generate change scripts from that, but it also allows you to export your database objects into a folder hierarchy organized by object type, with one [objectname].sql creation script per object in these directories. The object-type hierarchy is like this:
\Functions
\Security
\Security\Roles
\Security\Schemas
\Security\Users
\Stored Procedures
\Tables
If you dump your scripts to the same root directory after you make changes, you can use this to update your SVN repo, and keep a running history of each object individually.