Sorry if I came off the wrong way, but I mean to say that even though tank drive is tank drive, and it's all the same old song and dance, building the kitbot on steroids is generally a smarter decision for most teams because it provides the same benefits a normal tank drive chassis does (and all of the ones you posted), and it has something none of them do - You can build it in a day. That's the big hitter right here. Custom chassis can take a week or more to be sent off, machined, brought back, and put together. And I know you know that time is something very valuable in the FRC 6 week build season. The goal of a drivetrain/chassis is to be strong, efficient, and to effectively move the robot from point A to point B. The way you score is via your manipulator (Why am I saying this? You know it already.). I'd rather spend 6 weeks working on perfecting a manipulator that is better than everyone else's than spending a whole week or more making a chassis that does the same thing everyone else's does.

Tl;dr - You save lots of time by going KBoS instead of a custom chassis design, both drivetrains do the same thing, and both are equally as effective.