Nikita will sleep paws up sometimes but only when propped between my legs and the sofa or if in a basket or something. I've never see a cat do that on that flat a surface, it's really cute.
My Bootie also sleeps paws up - on her back, crammed into the very corner of the room (if she wanted to get further into the corner she'd need a triangular backbone!)
very cute, Seamus falls asleep like that at night, and if he's really knocked out, I'll put my arm on him and he hugs my arm... if he's half awake and I do that, watch out!