We just traded in our Explorer for a bright chili red Saturn Vue and the first thing DH and I had to do was decorate!
I have a Minnie Mouse antenna ball - the black matches part of the vehicle and the red bow matches the rest. When we were at WDW last month, we bought the magnetic "been there, done that, going back" bumper "sticker" and DH also found one that says "Magic Kingdom" and all the letters are made of Disney icons or characters. We also have a WDW vanity plate, so the whole effect is obnoxious and we love it!
If rearview mirror decs are illegal, maybe look into the mag bumper stickers? Or stick an antenna ball inside where you can see it?
btw - those danglers are fantastic!! And definitely on my list for our next trip.