Perhaps if we could give a recognition badge to all the skilled translators that could be enough as a reward.
Unfortunately, theymos won't patch the forum just to include the translator badge.
Such a "badge" could consist in a feedback left by the author of the original text to the translator, similar to the feedbacks left my 1miau or me. It would represent a recognition of translator's work (or, by case, a warning -- similar to the feedback I felt to gagux123 for his unprofessional attitude regarding translations).