I'm pretty sure that Lane Poor wide apertures are soapbars, so they'll require routing. Lane poor does make J sized pickups, but they're narrow aperture, and known to be pretty bright, crisp and clean - not far from what you've got.
But, there are lots of 5 string J style pickups available.
Measure your existing pickups carefully, including the the locations of the screw ears, and start checking around for replacements that'll fit.
EMG recently started making a JCS model - they're made to sound warmer and have a smoother attack. Might be just what you need, if they fit your routes......
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Otherwise, try Bartolini, Seymour Duncan, Sadowsky, Nordstrand, Lindy Fralin, Aero, Dimarzio, etc.
Some of these companies do custom work, too, so if you're not finding what you need, contact them directly to see if they can make something for you. It's usually not much more expensive than regular stock. Not sure if EMG still does custom work, but they used to. I know Duncan, Nordstrand, Fralin, and Aero all do custom stuff.
Also keep in mind that a lot of jazz pickups have separate, removable covers, so you might be able to get some off the shelf pickups and have some nice wood covers made for them that'll fit your bass.
You can certainly find some J pickups that are warmer than standard EMG Js. Maybe not as warm and fat as a big wide soapbar style humbucker, but definitely warmer than what you've got.
Standard EMG Js are known to be among the most precise, crisp, clean pickups you can buy.
