I picked up, (no pun intended) a set of these recently
http://www.ebay.com/itm/JAZZ-FAT-POL...E:L:OC:US:3160
They did not neatly drop into my existing pickup space and i had to do quite a bit filing on the plastic cases to get them to slide in. I was curious about the sound for the price and was putting them into one of my beater basses, so I didn't care about chewing them up to get them installed.
Once installed they are actually not bad sounding -- a bit on the aggressive side for my tastes (i play jazz and i dont mean fusion) with pronounced mids. I would not give them highest marks for clarity, but with a bit of the top tamed out in eq and a bottom boost they are serviceable passive pickups.