you know, the whole thing of kinda personalizing your vehicle made me think of something else...
What if there was a way of giving players gameplay incentive on being attached their vehicles.
For example, each time you score damage or spend money in that particular vehicle (donations do not count), it kinda goes to some invisible tally independent of rank. And as the tally goes up you get subtle bonuses for that vehicle alone. Nothing major, just tiny percentage increases to damage, speed, or damage resistance to represent luck or pilot skill.
So you present players with the choice, do i want to keep rockin in this shadowcat that i've repaired a dozen times and have become a beast in, or do i get a bigger mech that i have to start over with. I don't want to see ullers shrugging off heavy gausses, or coring assault mechs with a single medium laser burst, so there's gotta be some maximum cap, but it'd be interesting to have slight subtle differences between a fresh mech and one that has survived a dozen fights. Perhaps the banners and custom paints are visual markers of this?