So to the OP : Why the question? Is this something you're interested in having? I'd think the bass would be rather...well, not all that good sounging, ya know? Get this: Years ago, and I do mean YEARS ago, I had a local shop build me a J-bass that was routed like a strat, so I had 3 J p'ups and a lever just like strat. It actually sounded pretty cool, particularly in the "out of phase" positions... But I also had phase correction switches so that I could combing the p'ups in phase - Neck+mid, mid+bridge and a last switch to allow Neck+bridge. It sounded pretty darn cool, as I sit and think on it... but I recall mostly liking the out of phase positions and the combined mid/bridge - - the mid/neck in phase was farty, if you follow...
I have to think I'm not the only guy who has given that a whirl...