I would suggest the Mormons. Leaderhead: Brigham Young. If you would like some concept art, I could get you some. For an Industrial-era scenario I've wanted to do, but lacked the graphics for it.
A little historical context.
The Mormon Church, or the Church of Jesus Christ of Latter-Day Saints, as it is formally called, has a controversial history. Begun in 1820 in New York, it began slowly but soon moved to Ohio to escape persecution. From the beginning, a Zionist and Millenialist streak in Mormon doctrine made them distrusted by neighbors. They tended to stick together, help one another out, and congregated in central locations as much as possible. This owed to the belief that a new Millenium was about to arrive, and that they were supposed to prepare for it by building Zion somewhere on the American continent. Persecutions continued, and the Mormon leader, Joseph Smith, revealed that the location of Zion would be in Missouri. Converts continued to swell the Mormon ranks, and when the church moved en masse to the area of Independence Missouri, they created much suspicion and antagonism among their neighbors. In a frontier area, such a large influx of people (who voted as a single block and were more industrious than their woodsmen neighbors) created political destabilization. In a pro-slavery state, the Mormons were especially disliked for their anti-slavery beliefs. Tensions with Missourians erupted into warfare, and the Mormons faced an extermination order signed by the state governor. Their leaders were incarcerated and the Mormon zionists were driven from the state.
A new beginning in Illinois on the banks of the Mississippi river at Nauvoo seemed to go well at first. Their new "Zion" grew rapidly and the Mormons enjoyed prosperity under a unique city charter--one that even granted them the right to maintain a standing militia, with Joseph Smith as commander. As thousands of converts poured in from successful missionary efforts in England, Nauvoo became the largest city in Illinois for a time, even rivaling Chicago. The separatist mentality of the Mormons, along with their continued tendency to vote as a single political block, continued to make them enemies in the state legislature. The Mormons believed that their new Zion was to grow and fill the whole earth, and Joseph Smith even ran for president of the United States.
The Nauvoo period ended with the martyrdom of Joseph Smith, whom the Mormons followed as a prophet. He was killed by an angry mob, and the Mormons were threatened with open warfare if they did not leave the state soon. Brigham Young, the head apostle of the church, assumed leadership of the Mormons and began preparations for a massive exodus outside the borders of the United States, to the Rocky Mountains in the West. Joseph Smith had indicated his belief that the Mormons would eventually go there to find peace and refuge, and the time had arrived for them to go. The massive migration from Illinois to the Great Salt Lake Valley (in present-day Utah) was the largest single migration in U.S. history. Many died along the way. Converts continued to pour in from Europe, the U.S., and the Pacific for the next half century under a zionist doctrine that required Mormons to concentrate in a central location. The new Zion in the deserts and mountains of the West was called Deseret, after a Book of Mormon word for the industrious honeybee, and the people prided themselves in their industry. Brigham Young led the exiled people in carving out an empire from the dry and barren valleys of what is now Utah, Idaho, Colorado, Nevada, and even parts of California. If they had been allowed to fully realize their dream of a theocratic state in the western U.S., the State of Deseret would have been larger than Texas.
Reports of polygamous practices among the Mormons led to the United States Congress sending an army to Deseret to keep an eye on the Mormons. The largest peacetime army in U.S. history was assembled and marched to Salt Lake City to make sure that the Mormons did not have any unfriendly plans against the U.S. The occupying force found the Mormons wary and ready to burn their entire city rather than surrender it to U.S. troops. When assured of the Mormon's intent on peace, the troops restationed themselves in a fort to the south of the city. The Mormon War, as it became known, was settled without any bloodshed between Mormons and U.S. forces.
The Mormons applied for statehood in the United States, but were rejected because of fears about Mormon power, and also because it would destabalize the balance between pro- and anti-slavery states (prior to the U.S. Civil War). After the war, petitions for statehood were rejected because of objections to polygamy, which was seen as an evil practice on par with slavery. Political campaigns in the U.S. had vowed to eradicate the two relics of barbarism, polygamy and slavery, and politicians in Washington were still intent on eliminating the Mormon practice of having plural wives. Laws were passed outlawing polygamy, and Mormon leaders had to go into hiding to escape capture. It was only under the threat of complete disenfranchisement was threatened, including the loss of their all-important temples, that Mormons agreed to give up the practice. The prophet at the time, Wiford Woodruff, issued a degree rescinding polygamy. Some time later, the Mormons were finally able to join the Union as a state, called Utah. The original State of Deseret had been trimmed down by more than 2/3s, as other states around Utah were allowed to enter the U.S. ahead of the Mormons.
I've been interested for awhile in playing an Industrial-age scenario with the U.S., Mexico, and other nations vying for control of the West. The Mormons would have been a major force in the race to colonization. I would recommend giving them the traits of religious and industrious, with Brigham Young as leaderhead. Although he was not the founder of the church, his 40-year term as leader of the church was what brought it stability, a permanent home, and established the doctrines and practices that would guide the zionist movement for over 100 years beyond his death.
