Nope. The category 4's are all the same size. An option would be to book 2 cat 4's with connecting doors if you want.
We've had both styles of the category 3. We had our family of 5 in the standard size and it was fine for sleeping arrangements, but getting out onto the verandah when all the beds were open was nearly impossible. DH and I just returned from our parents only trip and we had the mid-ship category 3 this time. The verandah is much larger. We had 4 regular chairs, a table and a lounge chair out there and still had plenty of room to walk around. There were 3 sets of sliding glass doors and the murphy bed was in the living room instead of the bedroom. We didn't need it on this trip, but it was a much more convenient set up.
Tammi