K.M.
We had a similar problem. We told our son that we talked to the doctor and he said it was very important that he stay in his bed all night. That sleeping in his own bed was the best way for him to be healthy and grow up big and strong and to have lots of energy for running fast the next day. We usually talk about all the things we have planned for the next day that he will need energy for. We really praise him in the morning when he sleeps through the night (Wow! You must have lots of energy b/c you slept really well! Good Job! etc). We were all ready to give him prizes or start a sticker chart or something but just the praise seems to be enough.
Telling him the Dr said so keeps him from trying to argue his case with us or talk his way out of it. We have a fan going in his room for white noise so other noises won't wake him up. Our son hasn't attached to a blanket/stuffed animal etc but that has helped our nephews...
Is he still in diapers at night? Our 18 mo old wakes up and cries for a few seconds when he pees at night. Who knows... maybe your son is in a growth spurt or something.
Good luck finding what works for him!
K.