All of the VWL studios have the sleep sofa. Many people have described the DVC sofas as comfortable- some have not. I guess it depends on personal taste!
There are some dedicated 2BR villas at VWL- which have 2 queen beds in the 2nd BR. Lock off 2BR's will have the sleep sofa. It will depend on which type you get. You can make a request for a dedicated 2BR if that is what you want.
Good Luck!