I've been thinking about the OP's question over the last day or so, and came up with an idea. The question asked by the OP is how can or do you raise the head of the bed in an RV. Here's something I came up with.
Most beds in an RV are built over the wooden box (storage area) that's attached to the floor. The plywood used on that box, where the mattress rests, is usually split in two and hinged so the foot of the mattress will lift up and giving you access to the storage under the mattress.
Why not put something, or build a simple fold down frame that can be wedged between the top of the box and bottom of the plywood, causing the foot of the bed to be raised, much like a hospital bed, only, instead of the head raising, the foot raises. Then sleep backwards in the bed. (your head where your feet go and your feet where the head goes. At least, if you slide toward down toward your feet, the wall of the camper will prevent you from sliding onto the floor. Granted, you will not be able to see the television laying opposite end of the bed, but if you flip into the direction when you finally decide to close your eyes, it's an easy solution to raise your head. Also, you can adjust the height by simply putting different sizes (height) of wedges there.
Well, like I said, it was just a thought to utilize the equipment you already have without doing any re-construction or remodeling, or spending a ton of money on a hospital bed that does everything but vibrate!
As a kid, I loved to sleep opposite end in my bed. Sometimes I still do. Actually, with the king size bed in our bed-room (house), my wife and I will often sleep sideways across the bed so we can lay on our sides and watch television. Often we fall asleep this direction. Television is on a timer and shuts itself off. It's a good night sleep.