The Beal Escaper may challenge your sensibilities. The Escaper is clever design that allows a descending party to rig their rappel as a retrievable single line. Not only can you ditch the weight and bulk of the second rope, but in many cases the Escaper will allow you to carry a shorter, and thus, lighter rope because you will have eliminated the need to double your line through the anchor.
How does it work? Just thread the included length of dry-treated rope through the anchor and into a Dyneema "finger cuff", then tie your rappel line into the end-loop on the Escaper. You’ll descend your rappel line while (hopefully) keeping constant tension on the system. When you reach the bottom of your rappel, give a few tugs to tension and release the system and the rope will inch out of the finger-cuff. This allows you to retrieve your rope and the Escaper as one. Happy escaping!