I'm more familiar with Vanagons, but I have the Westfalia Weekender, which has a full width seat, a fold-up table that is attached to the wall and a rear facing seat behind the driver. This seat is mounted on a "box" base - the bottom cushion flips up to reveal great storage. I believe similar is available for the Bus.
Our van seats 6 this way. I like this interior a lot. With innovation, you could perhaps make a berth that would span the rear facing seat to the rear seat, giving you 2 up, 2 down, and one along the side! Of course a child cot may be the way to go for a few years. Just a thought.
John