How about--
- not using a translation extension;
- setting the default (= menu display and so on) language to Lojban (logged in users may be able to change it for themselves);
- letting everybody write in what language(s) (s)he prefers;
- using tags ('categories'?) like 'eng', 'deu', 'jbo', ... whatever;
- preparing templates like 'This is a translation of [[bla]].' or 'Cf. [[corresponding page]] in [[language]].' to be used where seen fit?A bit chaotic perhaps, but less demanding for users/editors, I believe.
-iesk