I had some of the same questions as Carolyn.
For me personally, my weight did keep going up. I was at 220 for a while... then 250ish... then it just kept going up. Honestly, had it stayed the same, I might have just accepted it and not really done anything about it.
Certainly I have run across a number of people (especially in the 300+ group) who have similar issues.
I don't know that there has been much research on the morbidly obese. The notion of a "set point" might not hold true for that group...
My 5 C's of healthy living: Commitment to conscious control, with the understanding that choices have consequences