For vets awards like decals and dyes are not very exciting, so throw in your ideas for future clan awards (little birdie told me that this is just a beginning of this system).
My ideas are:
1) Coupon for shop purchases for like 1-2$ to get people hooked up and actually browse the shop even when they didn't want to buy anything (perhaps they will see some cool stuff and change their minds). Also this is great because it gives you a lot of freedom regarding your prize.
2) Most straight-forward and least desired by Devs way of course is to make some outfits, hats etc. availible ONLY through clan leveling (and shop)