Fedora (pronounced /fəˈdɔrə/) is an RPM-based, general purpose operating system built on top of the Linux kernel, developed by the community-supported Fedora Project and sponsored by Red Hat. Fedora's mission statement is: "Fedora is about the rapid progress of Free and Open Source software."
We tried out out SMW for test case management for Fedora QA. We see SMW as a flexible way to prototype test case management systems so we can find out the design that'll work for us (and make a dedicated app for that, 1-3 years down the line).
For an example of usage, see https://fedoraproject.org/wiki/Test_Day:2009-09-03_SoaS#Test_Results. Design and setup process for this setup is documented exhaustively, too: http://meetbot.fedoraproject.org/fedora-qa/2009-09-02/fedora-qa.2009-09-02-14.14.log.html
The setup worked well for the initial run, but the setup time/skill needed and the daily press of QA needs meant nobody had time to implement & train folks in using it down the road, so current QA is still being done using the old system. (The switching cost was too high and the payoffs not concretely awesome enough, basically.) If someone wanted to champion Semantic MediaWiki's usage and implementation within the Fedora community and felt like stepping up to drive an effort for 6-8 months or so, I think they'd find a lot of support for it -- but willingness to take leadership in this realm is definitely needed for further implementation. I'd love to talk with anyone who's interested in doing this; I'm one of the folks who would support and help this, but doesn't have the bandwidth to drive it.
A potential fantastic summer or semester-length project for a willing student.