I've spoken with folx at Linterweb, who maintain a deposit of zeno-formatted[1] dumps at http://www.okawix.com/zenos/

Files ending in .okawix are tar files.

They plan to increase the frequency, and are moving FR, DE, EN, ES, and PT to another server for particular support.

This information was via Nytux at irc://irc.freenode.net/Linterweb

Amgine

[1] Zeno format information I've only been able to find in German at http://www.openzim.org/Zeno_File_Format and http://www.digitale-bibliothek.de/scripts/ts.dll?s=1&id=57107E74&mp=.... This was found via the ZIM format discussion at http://www.openzim.org/ZIM_File_Format