8 Gamma Coronae Borealis is all pristine metallic/rocky rings...and it has like 12 planets with well over 23 RES's total.
It has a decently outfitted station like .12ls away from a pristine metallic ring as well.
It's also more towards the edge of the bubble meaning that you're pretty much never going to encounter another player. It's the best RES/Mining place IMO in the game.
Also has a beautiful white A class star giving the whole system a nice eerie feel.
It doesn't match exactly what you need but consider it anyways I hope =]