I added a wiki package based on the CR Tcl API to HEAD. It should work on Oracle or Postgresql. It uses Wikit formatting rules. I borrowed the formatting procedures from Wikit.
It allows for permissioning based on the site node right now. That is, you can grant write and create on a site node basis. It would be possible to offer a link to set permissions per page. The code already checks permissions on a page level, so just links in the user interface to permission each page would be needed.
Its pretty rough, and has almost not features, but it shows what you can do.