Spring-loaded Sling Bed
The Spring-loaded Sling Bed would be an alternative to a foam or spring mattress. Different versions of the bed would be made to either rest on top of a platform bed (preferably one with an open bottom) or to replace the side rails of a bed. It is inspired by hammocks and the use of side rods as in the kanoe baby hammock (kanoe.us) and the "air chair".
I am not an engineer. There are some specifics of the design that I have left to someone with engineering skills. That said, I think this can be done. I also think that versions of such a bed could be made to accommodate very heavy or tall people or convert to a chair, loveseat or couch, but first things first. I would really like to see this made to replace the box spring and mattress of my and my husband's full size bed.
The bed would have a strong piece of fabric that would have two pockets on the left and right sides for metal rods to slide into. Some cushioning could be added to the rods or the pocket if it were done in such a way as to not prevent the rod from sliding in, was easily replaceable and didn't slow the drying of the fabric. A stopper of some sort would keep the fabric from sliding away from the ends of the rod. Some fabric would extend beyond the rod pockets and below the foot of the bed to serve as a bed skirt. There would also be some points at the head and foot of the fabric where it could attach to the frame to prevent sagging. Once the rods are inserted into the fabric, the ends of the rods would run along tracks or attach to members that run along tracks at the head and foot of the bed's frame. The rods would be pushed apart along this track by one spring for a twin bed, two for a full or larger (one for each person sleeping in it). The pressure of each spring could be adjusted by a dial. In full size and larger beds, there would be a fixed (not sliding), yet adjustable divider in the middle of each track. This would be the point from which each spring would press. The fabric could also be stretched between these points to prevent sagging there.
To make it more like lying diagonally in a real hammock, you could use Mayan or Nicaraguan hammocks tied diagonally to fit this bed or cut the fabric on the bias for a sort of Brazilian hammock. Also, introducing a means of making the fabric wider or narrower at certain points between the rods could allow one to customize support to different areas of their body.
Reward: A free or substantially discounted one.