I made WAS from my car on 10m in a single weekend, during the ARRL 10m contest, December 1989m while changing locations. (Spent half the contest operating from the beach in Malibu, and half the contest operating from a mountaintop overlooking Malibu, all within 15 miles of my home QTH.) However, 5 band WAS would obviously be a lot more difficult, and I've never even tried! I'd think 80 meters, especially, would be quite a challenge.
Yet, I'm willing to bet others have already done it. After all, HF mobile operations have been going on since before WW2, and really picked up with the introduction of the Gonset mobile rigs in the 1950's. Nowadays, with the dozens of tiny and high-quality HF mobile rigs available, I've got to believe that not only mobile 5BWAS, but probably mobile 5BDXCC have been achieved by now. You might post this question to the League's cognizant awards managers and see if they have any data.
Keep up the good work!
73 de Steve, WB2WIK/6