Definitely try the Welchol. I've been on it about three years now, I think, and I love it. It's the reason why I have normal poops.
I did get into a bad spell last year hurting real bad and having D everyday. I tried calcium (at first yogurt, then supplements) and that took away the pain. My theory is that I had irritated my guts eating things I shouldn't have--including sugar alcohol--and calcium is known to soothe GI tract irritations. If you haven't tried it yet, try some Calrate 600 w/ vitamin D twice a day. It is also slightly constipating, so it may take care of your loose stools all on its own.
The other thing I found is that foods that bothered me when my gall bladder was bad still bother me some now. Caffeine is one thing I really can't have. I also have to go light on super fatty foods--like ice cream--and greasy/fried foods, like pizza and fast food.