Design your own. There's a domain service called Hover.com (owned by Tucows) where you can buy your own short domains and set up your own vanity shortener URLs on them. You can use .com or .net .info or any of the new extensions. I just set up cwd.link as a shortener for our social links on our new business cards - We're Cyberwalker Digital (CWD) and so cwd.link/tw is the link we use on the cards to our Twitter account and cwd.link/fb for Facebook