i was thinking that a raiding culture would evolve around the Appalachian Peoples. These Appalcahians would grow in power and take over a large part of the Americas toppling the Mound Builders and the North Eastern Hunter Gatherers. By the time the Europeans arrive an Aztec/Incan culture has evolved in the centered on a city in the Appalachians.
I think that a raiding culture akin to the Huns or Mongols best develops in areas where resources are best acquired by raiding. And llamas aren't the ideal raider mount... Perhaps an Incan-like culture, but probably not Mongol.
http://members.aol.com/dalecoz/alt1198.htmI think that there is actually already a fairly developed idea along these lines. Look up the Alternate History Newsletter. Its in there.
A Species of Llama develops in the Appalachians. Natives domesticate it as Pack animal. They soon become a United Empire and after conquering the Appalachians they become the Mongols of North America
I don't know if this is what you mean, but I (also?) think that, to have a "mongol-type" culture, you need to have something to raid. If you had horses or cammels instead of llamas, you could have that kind of culture in present day Northern Mexico and Texas, as they could raid the agricultural "civilized" societies of Central Mexico. But to have them elsewhere in North America, you might need first a developped sedentarian society/"empire" in, let's say, the Missisipi valley.
Even if Llamas are not as efective as those animals, if you were able to make them "apt" to live in temperate lower altitudes, you can still have a nomad people simmilar to ancient middle eastern goat-herders. They would not be as agressive as the Huns or Mongols, but they might be similar to the Semitic peoples in the 2nd millenium BC, who lived outside the sedentarian societies in Mesopotamia and Egypt.
So, to sum up, to make the nomad scenario work well, an sedentarian society in the Missisipi and/or the Appalachian (this one like the Aztecs or the Incas) would help. As well as making llamas apt for the plains climate.
Wouldn't it just be much easier to let the north American horses survive the end of the last ice age, along with the North American camels and lama's?
Lama's can carry small loads, but they can't carry a human being bigger than a child, so it would take quite a bit of evolution before there's a lama that's big, strong, and fast enough to carry mounted warriors and archers.
Really, letting North American horses survive and then be domesticated by the Native Americans would be much easier.