I just did a bit of a round up of the total cost of the board.
Other than the cores, the other material was bought in one-off quantities so no volume discounts.
Due to the transport costs there would be some economies of scale by buying 2x the quantity. Also, buying the cores in 100x1400x6 planks was expensive. I think that buying the kiteboard blanks or larger planks an milling it myself would save a lot.
Also, buying larger quantities of resin reduces (4 kg vs 1 kg) saves around 30% and buying 4 sets of pads and fins reduces the cost buy around $20 per set.
There is also scope to reduce the volume of resin used.
I don't believe there is any discounts on other materials until you start to buy industrial quantities.
So with the discounts I can access I reckon $250 for a complete board with accessories might be possible.
I'd be very interested know how this stacks up with other peoples costs.