not that I know of. Various suggestions of sleeping with a body pillow exist. Hammocks exist. Plenty of people take naps on couches or in reclining chairs.
I wonder if it has anything to do with ease of manufacture.
I am sure you have read this: www.lesswrong.com/r/discussion/lw/mvf/
(relevant side note) Traditional Japanese beds are harder and thinner than western beds.
I am sure you have read this: www.lesswrong.com/r/discussion/lw/mvf/
As far as I can see it doesn't discuss sleeping surfaces that aren't flat.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.