Well, I said that, but that was judging from how the window bays were and I didn't account (or note) that the engine compartment and rear overhang is quite a bit longer than a normal E400 (which has a smaller engine, and hence a shorter rear overhang). Put it into perspective, this is what a 10.1m E400 should look like, and you can really see how much shorter the rear overhang is:
It is interesting to compare this to a E400 bodied 2-axle B9TL, which also has a big engine compartment, which is a tiny little bit shorter. That said, it's still shorter than the a E400 Scania.
FY3401: How much more power do you want? The E400 is 10% lighter than a E500 with only 20bhp short. I won't call that thing underpowered, not even slightly.