Well... never say never!
I've had success with fake "vagina" type toys. Can't get the depth bio guys can, but a lot of them are made very... erm... snug fitting, so they still give the desired affect. The anus ones seem tighter than the vagina ones.
Also had success with those jelly rubber cock rings, they are nice. When lubed they are too slippery to stay on for long, though.