Here are my findings from when I researched the 70's accessory the rear tent, this company still make them and here are the pics of what I found to be available. 429 euros seems a little steep for what it is, but according to their web site, its better quality than the original. http://www.bus-ok.eu/product_info.php?products_id=2842
What would you do with that space? It seems a bit pointless, other than I suppose letting more light in, or you happen to be 7th tall and need more legroom when sleeping.
