I wasn't sure whether to post ideas for Buena Vista Street in this forum or the regular forum. How about if the Red Car is joined by 1920's limousines, with the chauffer treating you like an important movie star on the way to a premiere? And then a creepy puppet agent yells at you about being late. (Just kidding about the last part ;) ).
They would be to the Red Car sort of like the horseless carriages to Main Street's horse-drawn streetcar.
(The main issue I would see is the how the crowds would be affected by additional traffic, but it seems to work on Main Street :) )