[EricH]

6WD variations
-Live Axle
-Dead Axle

-Drop Center
-Corner Omni
-Force it (no drop, no omni--see Team 25)

-Cantilever
-Non-Cantilever

-Direct Drive
-Chain/Belt/Gear Only

-Shifting
-Non-Shifting

Now, which of those options go into a "straight up" 6WD?

Spoiler for Rhetorical question answer:

All of them. It just depends which team you're asking.

The classic WCD is a live axle, drop center, cantilever, direct drive/chain combination, shifting drivetrain. Different teams have different tweaks to that drivetrain.