Normally, when replacing a rivet, one would drill it out and just replace it. These rims are probably double walled. I am not sure if the rivet goes through both walls or is just on the outside wall. If it is on the outside wall, part of the rivet will be trapped between the layers when I drill it out.

If I like the black look then I could always buy a 27" aluminum (must be solid(only) aluminum to anodize because the process will eat other materials) rim and have it anodized.

I could also switch to 700 rims but that would require modifying the breaking system and probably a few other things.