This may already exist in some form but I confess I haven’t checked. I am aware of competitions in tank training but they strike me as casual and insufficient for real combat simulations.
So here is my idea; take the 24 hour endurance testing of LeMans racing + the track from rally racing + shooting stations and penalty laps from biathlon + armoured vehicles = tankathlon
Throughout the race conditions, routes etcetera should randomly change. Such as after 12 hours each crew has 20 minutes to replace their engine or suffer a penalty lap for every minute over. Another example would be moving the pit stops and crews being radio silent having to figure out how to find them. The possibilities to create realistic scenarios mid race would be limited to the race directors imagination and sadism.
This would test the ability of crews and machines in sustained, high tempo operations. It would expose training and equipment deficiencies before being sent into a high tempo operation. To ensure that units don’t focus on training for the race only or have specific race crews, random draws should be held to select each units representatives. Teams could be individual vehicles to whole troops or squadrons. This style of endurance marathon would test any form of unit.
Victory would be the best time as in any racing but the benefits of discovering flaws in training and equipment will benefit even those not directly involved in competition. Broader combined arms competitions could be attempted to practice cohesion and identify problems. Friendly competition doesn’t hurt, especially if it improves training and leads to success.