Cardan / shaft drive for bicycle

Question for the bicycle experts!
Where can I buy a 7 gear shaftdrive / cardan for bicycle (the part only)?

A friend in Holland have tried contacting Beixo and Brik but they don't sell the part alone. I tried to contact the sussex company in Taiwan and China specialized in chainless bicycle but no answer, maybe not yet up to date.
Otherwise do you know shops that specialise in chainless recumbent bikes? Or possibly a place where I can buy second hand parts? Any help to narrow down my search is appreciated! �

Wondering why...? We are two adventurous who are building a bicycle prototype to tour Eurasia.

Please message me if you have any tips or contacts! Thanks

Here is a link of what I need in orange :
http://cdn.gadgetsmagazine.nl/wp-content/uploads/2014/09/BRIK-Brut-Cardanas-770x444.jpg