Yesterday I received some really good news. The guys at Geva Sales in Windhoek informed me that they will be able to access 0.5 mm thick sheet spring steel for me. It would enable me to build all the backsaws that I can not buy in Namibia. I am planning to kickoff with two Tenon saws (one cross cut and one rip) and a Dovetail saw.
I will keep you posted on the progress. Anyone who wants to build their own saw can benefit from looking at the websites listed on the library page of this site, especially http://www.backsaw.net/