Gene-doctors or Elfin Magic

In the world of Athena Minerva in the 22nd century in North America when selective body modification technology is so advanced as to be commonplace, a group of accomplished bioengineering doctors, (who are quick to claim that they are not a cult, which is exactly what cult members often say), worked out a genetic design for a long-lived human, starting with the light frame of an octogenarian human, adding increased muscle mass and bone density, and applying beautiful skin. They dubbed this design the "elf", a name taken from mythology.
Miniaturization of medical equipment had progressed since the 20th and 21st centuries and had shown smaller to be superior. The smaller the incision to repair structures of the body, the faster the body recovered. By early in the 22nd century, "micropresence" for surgeons had become commonplace, using milimeter-scale robotics to enter the body and observe in a virtual sensorium as if the doctor had been shrunken to the size of a grain of sand yet still had all his tools available. At the time some industrial robots were a millimeter across, (called Micro-Electronic Mechanical Systems, MEMS), and functioned well for mechanical and computational purposes, but "Medical MEMS" had to be the smallest yet devised at the time, and were of course manufactured by larger MEMS. By the end of the same century, micropresence medical devices were significantly smaller than a millimeter. They could be called an early form of nanobots, but with an operational lifespan of only a few hours.
This cult of bioengineering doctors used a combination of physically rebuilding bones, muscles, skin, and internal organs, and rerouting nerves and blood vessels (accomplished by the aforementioned micropresence devices working inside the body) plus a few genetic biological alterations on the cellular level so that the body maintained the new form rather than trying to regrow into its previous structure.
Many of the doctors in the cult underwent the procedure to transform their own bodies into the elven (or 'elfin') design and loved it. They made their body modifications available to all for a price, and developed many other "designer bodies" aside from the elf. If you wanted to be a male or female, both or neither, faun or fairy, angel or demon, minotaur or troll, centaur or werewolf, they could accommodate.
It turned out of course that people are people, so people who chose any particular body type found that they had much in common with others who chose that same type. The world stayed as cliqueish as it was before, as could be expected. But in this case, one could select their clique and buy into it for a price. Being a "body poser" living in a body that did not fit your personality became socially somewhat shameful among some groups (young people) rather than accepting the body that Nature gave you. (The "shamefulness" originated in a few examples of a person buying a body modification to attempt to fit into a group for the perceived social status, such as a person of natural-born troll personality type modifying into the physical appearance of an angel. Pop singer, By George, explained the sentiment as, "Don't try to look like me; try to look like yourself.")
Elfin Doctors easily gained a reputation for being extremely skillful, far-sighted, and worth the prices they charged for their services.