Type 'D' FE buses come in all sizes from small to large. Small being defined as not much more than 20' long up to 40' long.
I am not sure exactly what you mean by chopping the butt and moving it forward. It may be easier to just get a shorter bus.
However, most people would agree that size matters and reducing the interior volume isn't always a good idea. If the purpose is to limit the amount of rear overhang of the chassis, I get that. If the purpose is to build a garage in the back of the bus, I get that as well.
The question still becomes why.
Here is a nice shorter bus with luggage compartments: https://www.goharlows.com/default.as...OwnedInventory
Here is one that is a bit longer: https://www.goharlows.com/default.as...OwnedInventory
Here is a long one that is a bit older but it has the advantage of having the high roof option: https://www.goharlows.com/default.as...OwnedInventory