In reply to phmcguin:
My trad quickdraws are 18cm minimum, with 2 x 30cm and 2 x trebled 60cm extenders - I'm really happy with that selection, if anything I would get more 60cm extenders as they are so versatile.
Don't worry about them dangling off your harness - it's not a problem, I don't even notice it. You'll also thank yourself when your runners don't lift out and you don't have monster rope drag.
Not sure how much trad you've done, but if you are new to it - you'll probably find you need to extend runners a lot more than you first expect, especially if you're using a single rope.