For the gear heads, depending on what you want to do with it, there are now a few specialist light weight kit available or coming available from various manufactures:

Edelrid Via Ferreta belay kit: for belaying a second for short sections on a via ferreta.

Mammut Rappel Kit: A combination of 6mm cord, with a tiny figure 8 and small carabiner.

Petzl will be releasing the RAD (Rescue and Descent) System, also using a 6mm cord. (different from the 'PETZL ADVANCED RAD KIT') http://www.thegearcaster.com/2015/01/sneak-peek-climbing-hardware-fall-2015.html