2Door did a nice Motorcycle seat. Maybe he will catch this post and share it as I am sure its exactly what your looking for. http://motorbicycling.com/f15/new-co...-my-11665.html
I don't know where it is at the moment. I ride my bikes more from a touring peddle bike stance or I have to walk around for an hour with my fist buried into the small of my back trying to stand up strait.
Some folks do really well with their knees folded into there chest I don't know how they pull it off?