That is a terrible layout, although they didn't show a huge amount of detail in the video.
It's not designed for tall Americans, for sure--that is only the mid-height roof on the Transit. At 5'10", I have only about 1" clearance, it's pretty claustrophobic. The highest roof option is the only thing that will sell in the US, IMHO.
The 148" wheelbase is a much better platform, even in the regular body style. The extended body on the 148" wheelbase is a very nice size for a conversion.
There is only about $4K difference between the smallest & largest sizes, that's a lot of cubic feet for the buck, and well worth it.
