You've pretty much ruled out extension - hanging up or racking - so that leaves compression. From the sound of it you could safely be bound straight out, arms to sides and legs either bound together or (if sexual access is desired) doubled up and bound individually, ankles to hips; or you could be folded or rolled up into a bundle and tied any number of ways to keep you that way. That is more than enough possibilities for helplessness and creative abuse.

Or as moptop notes, you could be stretched between the left wrist and ankle (an imaginative bondage expert could probably contrive a tie that put most of the pull on a loop above the calf, with only a safe amount of weight on the ankle itself), with the right side safely immobilised but not stretched. There are plenty of examples of asymmetric suspension in the photos on the sites linked to the Library.

Good luck!