There are so many basses available these days suitable for slapping that it really boils down to personal taste and comfort [wide neck, narrow neck, 4 string, 5 string, etc.]. Two of the more classic, traditional funk/slap basses are the Fender Jazz and the Musicman Stingray. You may recall that not too long ago, there was even a thread here in the club about slapping Alembics. I think the overall consensus was that they worked pretty darn well. I will say that for this type of playing, bolt-on and/or set necks often give a better slap sound. These necks tend to provide a punchier tone--especially in the mid and treble ranges--than neck-through instruments.
I may be wrong, but I don't know as how I'd get overly concerned with one type of pickup over another--tone can be set and adjusted pretty easily through the instrument's electronics and/or the amp.
I would also check out websites/videos for guys like Larry Graham, who kind of introduced slap to the electric bass back in the late 60's, Louis Johnson, Marcus Miller, Victor Wooten, Stanley Clarke, Mark King, and Flea to see what they use. I'm sure other club members can name a lot more bassists/basses you might want to consider as well.
Good luck!
Eric
(Message edited by alemberic on July 28, 2006)