I don't know... I think most folks missed the point (and maybe you made that easy to do). You don't care what people think in general of your expensive truck, you care what your employees think about your expensive truck. You recognize you've come in to a dysfunctional situation created by your predecessor. You understand that leadership isn't about positional authority but about the ability to win the hearts and minds of your employees, and you recognize that jealousy is real and can't be dismissed simply because it is immature.
You are wrestling with whether the potential envy exhibited by some of your employees will interfere with your new mission. That you would even consider to forego driving that beautiful machine to work because it might interfere with the mission, regardless of the reason, is evidence of the character your new boss has decided to pay a premium for.
Despite several claims to the contrary in this thread, the evidence of maturity is not lack of concern for what others think, but rather the willingness to defer some of your rights for the greater good (of your employer, in this case) because your mission is to get the most productive value from that group of people, and that is much easier to do when they respect you.
Having said all that, my sense is that your character will more than offset any initial envy shown by your team, especially if you've already given them a chance to know you before they meet the truck.