I recorded a Rockabilly band a while ago.
And his contrabass had two pickups. I´m not sure about the terminology here (it was my first and only rockabilly session), but the other pickup was only there for the really hard "slap" sound. It didn´t pick up any tone, just the "crack/slap",
like a distorted clock. I think he called that pickup "fisher"something...
As I said, I´m totally a newbie about contrabasses, but the band made very clear that the "slap" sound needs to be really present.
Maybe you can investigate a bit about this pickup if you find it interesting...
It was pretty easy to work with the bass sound since the two sounds were separated.
I think it turned out pretty cool, check it out! =) http://www.bornofsin.net/studiomt/Justine_Master.mp3