Hi. We have nightweaned fairly successfully. DS is 13 months old. We have our mattress on the floor so I nurse him to sleep in bed (usually between 9 and 10). I then don't nurse him again until around 4:30 AM.
I used Dr. Jay Gordon's plan (sort of) when DS was 11 months. I skipped the first step of the plan because it just didn't work for our situation at the time. It's funny but I have already forgotten the details
: but I think it was about 3 - 5 days where DS was really mad about not nursing. I just picked him up and held him and occasionally put him down on the bed when he began to squirm out of my arms (and then pick him back up again after he kicked and screamed a few minutes). I walked him around the room, rocked him, basically anything to get him to sleep besides the boob. A few times I got him to take a pacifier (which we have always used occasionally during the day....like when driving in the car, etc.). The whole process took an hour or two (I think) before he would fall asleep.
After 3 or 4 days (I think) I switched to not picking him up and just rubbing his back in bed, etc. Then I eventually didn't do anything (besides staying next to him in bed of course!) It has worked for us. I will say the first time I tried it I gave in after a half hour of crying because I couldn't deal with it. The second time I tried it I kept with it. The key is to not give up...it definitely was not easy for either of us. Now DS sometimes still gets up and will fuss for maybe 5 minutes, but he will lay back down and go to sleep on his own.
Last night for he slept from 10 until 4:30 and prior to nightweaning he nursed every 2 hours. So it can be done. Of course, like anything, you will know if it isn't the right time for you. I had just reached the end of my rope so the timing was right for us.
P.S. I just noticed that you said that you nurse on demand during the day. During the week DS takes a bottle from DH while I am at work. So he is already used to not nursing during certain periods so that might have helped our nightweaning situation.