J.G.
We did NOT do co-sleeping, so I can't speak from experience. But what my MIL did when she wanted her son (my husband) out of her bed when he was 2 yrs - she calls "Squeeze Play." He slept in themiddle of the bed. Each night they squeezed closer to him. He'd say "move over. I don't have any room." and they'd go on and on about what a 'big boy' he was and how "I don't have any room to move over on my side. You're just growing and growing into such a big boy...." They did that for a few nights that he got fed up not having any room and went to his bed on his own.
Just a thought.