Here's an interesting video about the Blue Bird Bus Co. Their first bus was built on a TT chassis. (Disregard the comment about the 31-hp Model T engine.)
This steel bodied bus is at the Henry Ford and has been displayed inside the museum. More here:
There is a Blue Bird No 1 school bus wood body on a TT chassis that looks very much like the first video at Mt Pleasant, Iowa. It is always on display at the Old Threshers there over Labor Day weekend.