All things are possible but could be very expensive depending on your particular floor plan. I have two opposing slides in my mh with a queen. The head fits quite tightly in the passenger slide, now way to expand it. When both slides are closed the foot slips under cabinets, and against the slide wall. So in my case not likely I could do a swap.
Would you even have room to construct a bigger platform for the large mattress?
2016 Newmar Bay Star Sport 3004
2015 Jeep Wrangler 2DR 4WD Sahara, Automatic, Hard Top/Sunrider