A number of years ago I built an M1IP for a friend. It was his son's tank in Korea in the early 90s. I can't remember the unit (and I gave him back all the photos after completing the model) but on one turret face was the unit insignia (a dragon in a shield) and on the other side was a rectangle with the four card suits in each corner, the word "ACES" under a large "A" in the center. On each side of the gun barrel was the tank's name: "ARES" for the god of war. The tank was dark green with black cammo and all markings were stencilled in black.
I never crewed an AFV, but when I was in Germany in the late 70s/early 80s, we had discreetly named most of the vehicles in our motor pool. We had an M880 (pick-up) that we called the Millenium Sparrow and a deuce-and-a-half known as the Battlescar Gallactica (both with twisted sci-fi names). The names were written on the logbooks and on the windshields with Magic Marker (which really made the battery commander and the first sergeant happy ...)
When my Dad was in Nam, he had an M151 named "Boom Boom" (sorry, but I won't translate for the kiddies) I have always wanted to model. Dad was always a little Dinky Dau and it was fun to listen to him try to explain that one to Mom.