This was my windsurf/SUP wagon in 2008. It fit my 9'8 SUP, 2 paddles, 3 windsurf boards, 4 sails, 2 masts, 2 booms, a surfboard, tent, 20L fuel and water bottles, 1 t-shirt, 2 shorts and crusty jocks
VW Transporter SWB. Fits an 11' board in now worries (due to the step through between the front seats) And all the other gear you could ever want, drives like as close to being a car as you will ever get from a van. And the diesel uses bugger all fuel.
Oh and mine is for sale
Second that....I bought a VW Multivan for the exact same reason. It is/was a 7 seater.....removed the rear bench seat and left the 2 single side by side seats in the rear so my board(s) fit straight up through the middle. Increased the amount of surfs significantly due to the fact of have my boards with me all the time.