Re: Active pickups for 6 string players.
The typical six string bass guitar pickup needs to be a full-frequency affair. The string spacing spread dictates the dimensions of the pickup. This, in turn, pretty much rules out recreating the characteristics of the classic electric bass guitar pickups of yore. (Three P coils, perhaps?)
As uOpt says, most instruments are going to arrive with a stock pickup that fulfils the brief. Tonal variations are achieved by active EQ and the controls of the user's amplifier.
The other thing with bass guitar generally is the need to fit in within a band or recording context. Too much "character" could prove to be a nuisance.