seeking source for unfinished pine panelling

[Anne]

To finish a renovation project (in Athens, GA), we need to purchase some unfinished pine panelling (ca. 15 feet wide by at least 6 ft high) which could be stained to match existing older pine panelled walls. We’re astonished to discover that Home Depot, Lowes etc only carry stuff which has been coated and will not take a stain. Any ideas of how to find a carry-out or order-from source in NE Georgia will be most appreciate!.