I would have Weber build a 26" smoker with a tall middle section containing 4 cooking grates and a big, well-sealed door that hinges open for access. Built on a frame with a work table on the side. An enclosed storage area below. Rubber tires so it can be rolled around.
Seriously, I wish Weber would merge the WSM and the Performer...to be able to buy a separate cart kit that you put an existing WSM into would be great.