I'm still quite sure that the Hanomag identification is wrong and was just a guess by someone looking at the Hanomag-like front. The L28 was much smaller: even with the bigger 2,5 t chassis it seated at most 18 passengers (see below). I can't say for sure what chassis is beneath the Böbel body, I couldn't even find any other German bus of the early 50's with these characteristic front wheels having just 2 vent holes. But my personal guess would be a Borgward BO 4000 chassis.