It just struck me that NOBODY (???) makes custom active pickups?! It's all passives when you look at custom winders.
Or are there any?
Not that I'm interested at the moment, but would be cool if there were any.
Because actives require more than just wire and magnets. The preamp has to match the coils and be good which generally requires a stack of prototyping and developing on top of the required knowledge of that kind of electronics. Add to that you'll need to either use discrete components which take a chunk of space, or you'll have to put up the cash for a minimum order of either custom ICs or SMD based circuitry.
That takes money, time and effort. Then you're left with only one preamp. What if you need a tweaked one for different coils? IM sure there are people who do it, but it's much more hassle than passive pickups which just require a few parts.