Sorry to join in so late here, since I am also a wohm toddler BFing mom I figured I'd chime in. I stopped pumping at around 13 months, but BF during the day on weekends. My supply seems to have adjusted fine. (This is in response to your question to Molly.)
After I stopped pumping DS got water in his sippy cup at daycare since he is allergic to cows' milk. At that time he was gaining fine, but he got sick over the holidays and lost some weight. Now we are going to see if he likes soy so we can get him some more calories.
Thanks for starting this thread!