So there is this Blue Button initiative, which pushes software vendors to add a blue button (https://www.healthit.gov/topic/health-it-initiatives/blue-button) on the software, indicating that the patient or doctor can download the medical record for a patient. It is now being proposed for implementation Medicare patients. This seems particularly promising as it would be the first time the patient could download their data from different Medicare providers and import them all into one single personal health record.
According to RollCall Providers can start enrolling now, apparently, and the CMS will roll out data in August. It sounds like the CMS, administering the Medicare program has control over that data, so it would all come from them.