What type of plywood, grade and thickness? In Durham, I am only aware of the borgs carrying hardwood veneered plywood, but would be interested if folks knew of other sources. There are certainly places in Raleigh, but if I had to drive anywhere, then my first choice would be the Hardwood Store of NC (see ad on the right). They're in Gibsonville which is about 45-60min from Durham depending on which part of the city you're in. They carry a good selection of hardwood plywoods in different grades and thicknesses and will cut it down (in half) for you.
Sam