Here's the "ultimate draw" setup: 2 light wiregates, a 24" mammut 8mm runner, and 2 dental/orthodontist rubberbands.
Double up the rubber bands around the ends of the draw next to the biner, so each carabiner will have one loop of the sling permanently attached. Then you can triple the slings alpine-draw style and you instantly have sport-climbing sized draws. Keep them racked as short draws, and quickly lengthen them without worrying about re-clipping any loops of webbing.
In order for the stiff/sewn part of the runner not to have to bend over a carabiner, make sure that one of the biners is attached next to the black sheath.
The dental rubber bands seem durable, and ridicuously cheap. Easy to pop off once you take out the carbiner. This setup would ideally use WC heliums or some other keynose carabiner, but that's a lot more $$ than on-sale superflys.