We are booked in 8542 on the Magic for this coming June. The room sleeps 5, which indicates it does have the Murphy bed.
I found this out by looking at Yahoo cruises. For the Wonder, I looked at August 31, 2003, which had 8542 available. It shows a maximum capacity for 5 for the Wonder as well.
There have been a couple of old posts from people who have stayed in this room, and they were positive. Of course, I forgot to bookmark them, and can't find them now.
When the Search function is turned back on, search for 8542 and you should be able to find them.