I just thought I would update this thread. We night weaned DS using Jay Gordon's method from Boxing Day last year. We have endured croup, 2 ear infections, a random virus, and molars in this time so it's been a bit of a long road with ups and downs, but when he isn't sick/in pain, DS is now sleeping through most nights! It means I am getting much better blocks of sleep which is great. The actual weaning process went much better than I thought - he accepted it really well once he got the idea.
The next issue is early wakings - he seems to think 4.30am-5am is a perfectly acceptable time to wake up. It's way too early for all of us, but my DD is particularly suffering as she gets woken and doesn't have a day nap any more. The problem is that changing his early waking (if it's even possible) is going to involve a very unhappy baby I think, which will wake her even more......arghhhhh......why can't kids just appreciate how wonderful sleep is?!?!?