We had no need of 4 seats. We've only had 4 people in the van once since we bought it. So I figured I'd make better use of the space and took one of the rear seats out. We had lots of good space now, but when it rained and we had to sit in the van, one sat in the front and the other sat in the back, and it wasn't very sociable. So, I modified the seat I had taken out of the back and put it in the front. I'll be getting it certified by an engineer, but as with most stuff I've made I've over-engineered it, its stronger than what was there originally so it should be no drama.
The result? We now have somewhere we can sit sociably. We have a spare bed if its needed. We have more storage space, and when I get around to makeing a nice folding table we'll have somewhere convenient to sit to have dinner. It'll also be perfect for when I turn it into a mobile office... (but thats another story :-) )