It's good to hear that you've gotten such high mileage on your dynohubs. Son hubs have a good reputation, but I'm especially impressed by what you've squeezed out of your Shimano hub. I have three of the first-generation "Joule" dynohubs (made by Sanyo, and similar in some respects to the Shimano hub). One of them experienced bearing failure after only about 2,000 miles. I was told these hubs are not serviceable. Since I had two spares, I undertook to "explore" the possibility of replacing the cartridge bearings. I was able to do this, with a few minor missteps, and posted a report on HubStripping. Hard to believe that was ten years ago.
Now my main dynohubs are SP. The one with about 9,000 miles on it needed a new rim at about 8,000 miles... I was debating whether to have the bearings replaced, but decided to rebuild the wheel and see how long the hub continues to work. I'm not sure I would attempt to replace the bearings myself, as the SP hubs appear to be more complex. I would probably feel the same about a Son hub.