You always have a chance, but certain things will definitely improve your odds. If you don't have the users/revenue, focus on your market size. Without either of those, showcase your amazing team. If you don't have an amazing team...spend 6 months locked in a basement coding, and become an amazing team.

Browse through http://yclist.com/ to see if any companies were small-market. Version 1 doesn't have to cater to a giant market, but you should have a plan to get there eventually (and be able to concisely express your plan).