We're planning a 10 wheel robot this year. 8 8" and 2 4" wheels in a 2015 KoP chassis. Yes, I know that the diameters on one side add up to 36" and the robot is only 32" long (before the wedge that we were going to add even before AM made it an easy COTS thing). Our wheels lie in 4 planes rather than two, and we currently have different treads for the inboard pair of 8" wheels than for the corner wheels. We haven't tested it yet in the real world (vice CAD), but we're on track to do so this Saturday. After
this post, I'm rather sanguine that we'll be able to cross the rock wall, moat, rough terrain, and ramparts as easily as the low bar.
Our ball pickup is going to double as lifter and lowerer to get through the portcullus and cheval de frise. Our basic designs just needed some minor tweaks to make this (virtually) work.
Finally, we're leaving the drawbridge and sally port as too easy to defeat via cooperation between two or three robots with working drive trains to waste a mechanism upon.