I took zyprexa for a very short time. I don't think I took it long enough to see any weight gain. I have read the same things as you've found.
One site I like is crazymeds.com.
Just remember -- everyone reacts differently to meds. May be you should give it a try and if it doesn't work out then go back to the doc and try something else. Interestingly enough (and I know you're not on it any more) but I actually lost weight when I got on Effexor.
hugs to you!