In my defense as Wycen's Farscape DM, I have submitted some stuff to various d20 publishers but unfortunately no reply.
I borrowed creatures liberally from the Monster Manual and even from Oriental Adventures. I found it frustrating that AEG wrote up random creatures but never developed stats for creatures from the show. Some people on AEG's forums have been trying to port over stuff from the show.
All in all, I found the system to be very clunky. Not surprising since it was before d20 Modern if I recall correctly. For example, while it was interesting to have each species have their own hit dice, it led to some statistical strangeness, such as the Delvian priest having more hit points and combat longevity than the Sebacean warrior/commando.
In the show, Zhaan was very tough (and I'm quite sure she could hold her own in a fight with Aeryn), but her character motivation reigned that in a lot, allowing Aeryn to be the sexy kick-arse chick she was.
In other words, as my game progressed, it felt less and less "Farscape," and more like some strange sci-fi game with the words Peacekeeper and Hynerian thrown in. YMMV.