Ziterdes modular gaming board comes closest I guess:
http://www.ziterdes.de/ziterdes/en/produkte/listview.php?catID=69&subcatID=99
Produced several years earlier, not that sturdy and with very visible edges of the boards.
Personally I prefer another solution:
I use coloured felt mats by Hotz Mats
http://www.hotzmats.com/felt_purchase_mat.html , esp. European Fields for Fantasy and Western Town mat/Moonscape/DirtPlanet (all without grid) for
40k. Zuzzy Mats
http://www.zuzzy.com/ (rubber, structured, unpainted, smelly at first) are an alternative for USA, but shipping costs are prohibitive for other destinations.
Mats are even more modular than modular boards, when you add hills, rivers and buildings freely on top.