We have a Chrysler mini van at work, and i'm sure it would fit a 750. But the amount of gas it uses is ridiculous. Bear in mind that gasprices are insane where we live. And roadtax for these cars is enough to make you cry.
If you want an economical option, I would buy a normal van without seats or windows in the back (grijs kenteken). Sure they are bigger, but you'll get used to parking it pretty fast.
We also have two VW vans, one brandnew and the other 10 years old. Everyone that drives it is in love with the older one. They are cheap to run, I drove it to Italy on one tank of diesel. And they have a lot of power too, they cruise at 150 km/h all day.
Perfect for your surfing trips, throw a matress in the back and you've got a place to sleep too.