I like the old Hawaiian method:

Burn a pile of wood into hot coals, down in a hole several feet deep.
As the fire burn down, put porous lava rocks into the fire.
When the rocks are hot, put them (with tongs, obviously) inside the dressed pig.
Put the pig in the hole on top of the coals.
Put the remaining hot rocks on the outside of the pig.
Cover it all with wet ti leaves on top.
Cover that with wet burlap bags (or tapa cloth if you are a purist).
Come back in about 8 hours and luau!
Got to get it hot enough to cook the trichinosis parasites.
Use lots of water, so it all gets steamed.

Or better yet, go down to a BBQ place and order a pulled pork sandwich.

But still, I think it is interesting that barbeequed pig is as old as humans lighting fires. We probably barbeequed pigs like this before we learned to speak.