You can bend your own fork blades by bending each blade one at a time, and this appears to be the main method. The right way to adjust the fork is with the kind of bender than bends both blades at a time, which is pretty unusual in the average shop. People do stuff like shove both blades under a door. The good news is that 8 mm isn't that much. And it is possible to bend the blades in sequence, but then it becomes essential to have a controlled method, and to have excellet measurement devices.
There are folks doing the bending, a pall of mine who lives over the border in NY, NY got someone to do him a fork, I have no idea whom, but it is out there. Conceptually custom builders should be doing custom front end geometry, and it takes the ability to get the forks right to do that. I have thought of doing it by kerfing the top of the fork, and then welding the kerf shut.