I maintain http://orionrobots.co.uk, and have also recommended tikiwiki for evaluation as a documentation tool of choice at my day job. -UPDATE - We are now using it for one system. However - we are running into resistance from users of trac. Its all free software - and we dont currently have a svn integration module that I am aware of.
I have added a few features to my tiki during the course of my work - mostly just small ones. I have started wrapping them up as mods - Have a look at Tiki Googlebar Module Mod and Tiki technorati tag Plugin Mod.
I have been working on a ZWikiToTikiWiki converter and also a WordToTikiWiki converter. Both are built in python. I have not cleaned them up - and I am not quite confident for their distribution yet - although I admit, having built, and ran the ZWiki converter as a quick and dirty operation, I never really picked it up again. It was written in my first few weeks of switching to Tiki (about 2 years or so now). Due to my lack of tiki knowledge at the time - a lot of HTML is generated with it. If anyone wanst to take its husk and carry on - please message me here or on OR.
I have added a bottom pages rank - so I can see which of my wiki pages are the lowest performers, and consider why. This patch was applied to OR, but cannot currently be placed in a mod.
I am also currently working to get Tikiwiki working on a webfusion shared host, and will log my findings once it works. -UPDATE - I have been running for anumber of months on this without probelms. WebFusion are indeed tiki friendly.
You may find me occasionally on the #tikiwiki irc channel, and sometimes online here.