Re: Ibanez Proline 2550 Super 7ft noisiest pickup ever?
I have them and I've got some ideas. Those pickups are somewhat hot and powered by two inverted ceramic magnets. The pole pieces aren't grounded, that could help but it's tough to do. Shielding the cavity will help. The guitar likely has shielding paint under the mounting insert, and a screw connecting a wire. I wouldn't trust that's doing it's job anymore. I'd put copper under the mounting insert and screw through that. (or solder to it)
I have two guitars with these, one is stock, the pickups were epoxied into the cover. The other I pulled the pickups out of the cover. It was more like hot glue. I made tall bobbins with Alnico magnets and they sound great, but two problems for you: You like the sound as-is, and yours may be epoxied. If they're hot glued (amber colored and rubbery) you could have them rebuilt, possibly as a stack, or slipping a Hot Rails type pickup in there.
Option 3: trade me the guitar
Option 4: trade me the pickups and mounting inserts LOL!