Speaking from my experiance in retail, especially working with corporate buyers, you need to be able to convince them that:
1. Your back end could handle much larger orders than your accostomed to.
2. Your marketing plan is established enough to ensure that your product will sell through at store level.
There are some instances of geographically local offerings at a retail level (your product only selling in sporting chains that are within your state) but generally their intention would be for you to be ready to go nation-wide sooner rather than later.
Starting online, establishing your brand, and possibly working with an established distributor might benefit you as well. The bottom line is there needs to be an accesible need for your product on whatever level you want to sell at (national interest for corporate chains).
Roger Kirkness
Twitter: @RogerKirkness
LinkedIn: http://www.linkedin.com/in/rogerkirkness