Currently, we just have DokuWiki setup on it's own site - we haven't done any integration with it - all we've done is added the header images and links so that it still looks like the SilverStripe site.
What would you want to see in an integration of SS and DokuWiki? Something as simple as single sign-on/authentication, or something more complex like editing wiki pages via the CMS? The CMS already has some features of a Wiki system - it keeps old versions of all documents, and you can compare two to see changes.
I think it would be better to have a complete wiki solution fully integrated into the SilverStripe. Besides, I have a question: can we have multiple blogs in one SS site (e.g. for team members separately)?