I'm not sure what your needs are, but this was our solution for extra sleeping space. We only have storage space for a small Class C, but have 4 children. My husband's solution was to convert the bed in the back into a bunk. It has worked beautifully. We now have a full size bunk in the back, the over head bunk and the table(which is only used if we have company).
Just thought I would give you another option in case it suits your needs.