Where to buy/How to build a Devanathan-Stachurski cell?
I would recommend you to do a research to find scientific articles on using DS cells. In this case if you have any specific questions you can try to contact authors directly, hopefully they will reply and be able to help you.

You can start from this article (Mike J. Danielson, Corrosion Science 2002 44 (4), pp. 829-840) http://www.sciencedirect.com/science/article/pii/S0010938X01001032. 
The author made his own DS cells as described follow