I used the wiki in a project hosted at Google Code. With this wiki all the changes you make with the web interface are committed in the subversion repository of the project.
For example, if you create the ExamplePage page using the wiki web interface the underlying software creates and commits a wiki/ExamplePage.wiki file in the subversion repository.
This should work in the inverse way. If you modify the subversion repository the web interface shows the new version of the wiki.
This is a nice features because let you edit files also with an external editor and then upload (commit) them to subversion.
Do you know some open source project that support this feature?
Haven't used it, but svnwiki seems it could be what you want.