Thanks for your email. Your best bet for tent camping and a bonfire on the beach is Hatteras Island and Ocracoke, all south of Nags Head. The northern end of the island (Corolla to Nags Head) do not permit fires on the beach. That is not the case in the Cape Hatteras National Seashore, which comprises Hatteras Island and Ocracoke. My best guess would be for you to look for NPS (National Park Service) camp sites. Here is a listing of campsites you might want to consider.
As you review the above camping link, consider the Oregon Inlet Campgrounds (this is an NPS campground) and those listed as south of Oregon Inlet. The description will tell you which ones have facilities for tents. Some of the private ones have warm water showers available as well (not sure how "camping" you want to go).
The towns to consider are: Rodanthe, Waves, Salvo, Avon, Buxton, Frisco, Hatteras Village and Ocracoke.
Good luck and have fun! Would love to hear about your OBX camping trip upon its completion.