Have a trawl through here: Modellbau -- Gabriel Stahlformenbau - Modellbaushop, Onlineshop, Modellbau, Modelleisenbahn, Vitrinen, Ruderhebel, Servohebel, Gabelhebel, Modellhubschrauber, Eisenbahnmodellbau, Flugmodelbau, Flugzeugmodellbau, Zubehör, Kugelgelenke, Werkzeugbau, Ku

They have better solutions than a standard clevis into a plastic arm but if you are set on that route their arms are pretty bomb proof.

Malcolm