Further to the discussion in the transformers Help and Ideas forum I designed legs that have the flexibility of genuine human legs.
They use function elements for the purpose of the small muscles and ratchet joints for the gluteal muscles (with the function elements used for fine tuning). I do not have the parts for it but I hope someone takes these joints and uses them for themselves!
Unfortunately, LDD does not allow poseability of the function elements.
This WAS built with vehicles in mind. The hip can rotate a full 180, allowing for the legs to fold forward like on Optimus Prime (with some creative torso-work).