SubWiki is an engine which is in very early stages of development. It uses Subversion for its data repository. It is implemented as a Python-based CGI script. Current version seems to be 0.1-dev.
Homepage: http://subwiki.tigris.org/
Subwiki wiki: http://www.webdav.org/wiki/projects/SubWiki
Assuming that SubWiki wiki is their showcase/flagship wiki, one would have to conclude that this software doesn't really work yet, and perhaps the project is stagnating/dead.
Obviously at this stage, spam is the least of their concerns. Back to AntiSpamRecommendations.