Finding sources willing to sell to home winemakers is tough for many in the USA. When I lived in NY, my business partner and I purchased from a couple of sources, one of which is still operating today, and we were able to buy an odd barrel of juice from a few wineries.
In the late 90's I found a couple of sources for grapes in the Winston-Salem area of NC, but wasn't happy with the grapes. In the past couple of years I've searched for sources in NC and VA, but haven't found anything. The state-wide grape growing organizations may have sales pages for winery-level purchases, but not for folks buying by the lug. I 'spose I can't blame the vineyard owners, as it's a lot less hassle to sell by the ton than by the lug.
I pay a premium for CA grapes, as they get shipped to Musto in CT, then to NC. I've considered Gino Pinto, as they have a facility on the north side of Richmond VA, but that's a 3+ hour trip in each direction. My ancient truck is fine for local trips, but I'm leery of making a long-distance trip.