Try the Underwood, I think it will give you the sound you are looking for. Ray Brown, Eddie Gomez and countless other jazz heavyweights had used them quite successfully for years.
Some may be of the opinion that the sound you are going for is a bit dated. But if that's how you hear it, then more power to you!
I have owned just about every pickup thats come out in the last few years, yet my Underwood still gets plenty of use. It's simple and it works. Right now the two basses I use most, a Shen carved bass and a Gage Czeck-Ease are sporting both Realist and Underwood pickups. Even the Czeck-Ease, which was designed with the Realist in mind often benefits from using the Underwood in boomy sounding rooms. The thing that's great about Underwoods, is that while they don't give you a 'just like your bass, only louder" tone is that they can almost always give you a sound that works live, even with loud bands. Depending on how you EQ, a sound that's pretty real sounding can be had with a minimum of hassle. In my experiance, it's just a matter of dialing out a little highs and mids, if anything at all. You know, the ear is a funny thing and can often be easily fooled into thinking a bass sound, even one that might be described as 'mid-rangey and compessed", as is often the case in this forum (even by me) can in the real world, a crowded noisy club for example be just the ticket for a great bass sound in the room with a band.
It's an "if it sounds like a bass, it sounds like a bass" kind of thing. You want to be heard, and you want to be able to hear yourself. I'm no big name star, nowhere near famous. But I manage to work constantly, 6 nights a week, nine months out of every year with terrific players in some of the greatest cities in the world. I wouldn't even think of leaving home without my Underwood!