I just noticed that local auction house has sold quite interesting double rifle in their auction 14.12.2013:

http://www.hagelstam.fi/catalog/product/view/id/152143/s/kaksoisluodikko/?s=true

John Blanch & Son, London, percussion double rifle, caliber .500, nro 5459, damascus barrels, with case. Hammer price: 1400€