I'm sorry to say I'm with JeRkY on this one, there is so much to cover before committing to spend any time or money making a design real. I also don't want to heap negativity on this project, but to encourage you to keep researching and looking at what's worked (and not worked) elsewhere, and why.
If you're definitely after a one-legged design, how about a large very stiff monocoque-style single chainstay with a pivot just above the BB and a shock either above the swingarm or inboard, inside the main frame. I'm thinking along the lines of motorbike rear ends... although that does then present a problem if you have a rear hub with one attachment point - the rear wheel needs to be driven, and also to brake.
It's late and I'm waffling, but do stick with it - this is an interesting project and it has potential! All the best.
If you're definitely after a one-legged design, how about a large very stiff monocoque-style single chainstay with a pivot just above the BB and a shock either above the swingarm or inboard, inside the main frame. I'm thinking along the lines of motorbike rear ends... although that does then present a problem if you have a rear hub with one attachment point - the rear wheel needs to be driven, and also to brake.
It's late and I'm waffling, but do stick with it - this is an interesting project and it has potential! All the best.