If we get human head transplants working, we can use regenerative cloning to create new bodies. It'll be the cure to aging, cancer, everything.

If not clones of the patient, we could use monoclonal bodies with O- blood and HLA neutrality to negate the need for immunosuppressants.

New thymuses and pulmonary systems regenerate immune and endothelial health of the brain.

We're close, we just need a conceptual jump. It sounds icky, but not in practicality.

Tangentially, we could use artificial chimeric pig uteruses to artificially give birth. It'd relieve the burden of bearing children.