dave after reading your post with AZ roadtrip ,( by the way cool report with old buses) , an idea came to my mind
time is to rebuild gasser or repop those one , and my idea is why don't to build the assistance truck of one of these gassers , and after seeing your flexible and other bus inthe tread , i just remember the LEE ELIMINATORS bus named "race central" i don't know if this one is a flexible , but it will be cool to build a replica of this one
here're some picture of the bus from keith cal look archive , and some other from magazine
keep growing the idea
fabs