I, too, think Russian would be a language to consider. I've encountered a group of very active Russian Hercules fans who have their own archives and mailing list, translate English stories and write their own stories in Russian, even make vids with Russian songs. Given that HtLJ is a small fandom to begin with, it seems likely that there's a larger Russian presence in other fandoms, too. (My English-to-Russian isn't good enough, alas, or I'd volunteer to translate.)

As a Dutch native speaker, I would volunteer to do a Dutch translation, but I am not sure it's needed - I'm not aware of any Dutch-language mediafannish activity at all, and the few Dutch fellow slash fans I know all write/read in English.