The Tambour door came from ebay and was £28.00.
The cup holder came from the rear centre arm rest of a Vauxhall Mokka,s seats which I was scrapping.
They are hard to come by on their own, but you could easily use a couple of single, 'insert' type ones instead.
The box was made using 9mm ply and I cut some corner profile from a piece of 75x75 softwood so it didn't look to boxy.
The outside was then carpet lined and the inside had 1mm rubber glued to the sides and cheap, rubber backed floor mat from Ikea, stuck to the bottom.
The top was cut from a bit of 15mm MDF and the apertures were then cut in it and routed.
I then primed the top before finishing it in several coats of Halfords, Anthracite wheel paint.
I understand it may not be everyone's cup o tea, but, for me, it utilises another fairly dead space in the van aswell as giving the rear passengers somewhere to put their drinks.