Cypher,
Terry is right about Oregon climate producing unique form. We find that the nursery plants grown there have annual extensions of 2-4 times what occur in our region. This produces comparatively taller trees with slender caliper. The forest-like climate at the Portland garden increases this effect. If you want a similar appearance, you could use a plant commonly seen as an understory shrub, such as Pieris, and prune to a tree-form. Reproducing a Northwest climate would also help; provide protection from drying winds, shade and lots of water, all the time. Starter material might be best found where inattention to a seed bed allowed many plants to reach for the available light, say in a neglected spot in a nursery (One time I purchased an entire group grown that way from someone who felt they were "unsellable"). I wonder if there is a Stewartia that can tolerate your dry heat. It seems they might be a species to investigate. Don, what do you think?
James