In the past, I have used these for parsing and database setup practice, making CSV and local databases that require no network access. I am mainly interested in the reference urls found in wikipedia pages.
No one who is actively marketing and encouraging contributions on a scale people are aware of them.
If they existed, you'd have told me who they were. ;)
Simply storing the data isn't enough, you'd need to maintain it and make it publicly available as a mirror of the site and encouraging people to interact so you have a community to work with in the event of Wikipedia's failure.
I guess my point is the OP should be doing that instead of bitching.