PIF,
I posted in the health thread...and I, too, wonder about an intestinal parasite. Is it possible that she has an immature bowel? Has she been treated for Giardia? I don't even know if cats get it...Binx had it for a month. Does Bramble go outside at all? I need to know more, graphically, about the actual thing she does produce. You can pm me, if it is too gross. What about IB? Is she able to access food all the time? Is it an allergy to I/D?

Good luck, and keep us posted.