I think @Paulo_Carvalho’s approach using the vtkVertex cell approach in a vtkUnstructuredGrid would be the best approach as far as data storage goes. However, if the mesh has any cells other than vertices (e.g. quads, triangles, tetrahedrals, etc.) then you’ll immediately run into problems with missing cell data (though I suppose you could just fill those cells with NaNs but that might turn into a whole lotta NaNs that have to be stored).
Also, I can’t really wrap my head around how you might display this kind of data… would you interpolate the values at the nodes for each 2/3D cell across the cell? Or how might you display two values at the same vertex without using some sort of geometric distortion?