Don't know where you can get one but if you go to the "Auto" section of these forums I'm pretty sure someone there will be able to help you.
Did you try to make the rack and surfboard yourself? A couple pieces of spare sprue and a piece of scrap plastic for a surfboard and you could have it done yourself. Give it a try. You might be surprised at what you can make if you put your mind to it.
Either way, good luck. Post some pics of your build. Let us know how you make out.
Stay Safe.
Jim 
Main WIP:
On the Bench: Artesania Latina (aka) Artists in the Latrine 1/75 Bluenose II
I keep hitting "escape", but I'm still here.