I know which one you are talking about. It looked like the arm of a crane - triangular form when viewed from head-on with side braces between the three main lengthwise elements (side braces also formed triangles with the lengthwise elements forming the third side of the triangle.
I remember red highlights for some reason, and a north European origin.
I remember seeing this at the same time as a Scheu tonearm, and for some reason I think it may have been the original or prototype version of the Scheu Cantus, but I am not sure. I'll have another think...
Alternatively, there was once a Norwegian tonearm (WKarlson?) which looked like it would have a lot of rigidity but a HUGE amount of horizontal mass, but that was made of metal, not wood.