I am aware that there have been many works on the problem of discretizing a surface into polygons, however, I wonder if in any work the problem of doing so to get polygons with edges of the same length has been discussed?
Edit: Just to be clear, I am interested not only in the case where the edges form polygons; all I want is the edges to be of the same length (and don't care if they enclose a 3D shape).

An interesting question. My immediate thought on it is that the curvature of the surface that one can represent will be rather restricted. If you fix an edge length, you will often need to have discretized points that lie outside of the original surface.
Think about regular triangles, they have a limited set of curvatures. If you use anything other than these triangles, it is not given that all the points can lie in the plane.
Perhaps there is always a trivial solution where you have one big polygon with lots of edges, perhaps its not convex. But this seems to run counter to the original purpose of discretization.