I would ask on conifers forum for drought tolerant selections. I have two dwarf conifers, but they are both high water plants as trees go. You don't want them look brown and ratty.

I grew Golden Arborvitae out at the front house here in Simi Valley, and once established they were never watered. They got to be about 8' tall, they were gorgeous, and they were wonderful at Christmas for greenery. I only took them out because we had to- we replaced the old fence and these two old beauties were in the way.

I recently planted two dwarf ones in my back rose garden, but I don't think they will get enough sun. I love the chartreuse color with the dark red roses- I sure hope they make it. I recommend them very highly- I can't think of a single drawback. They will get pretty big if they get regular water- I don't know how big, but I have a friend with one that is about ten feet tall. They are not skinny, though- not exclamation point skinny, anyway.
Renee

I just remembered that hoovb mentioned Skyrocket cypress a while back. You may want to check that out.
Renee

My favorite for your purpose is the Irish Yew or Taxus Stricta. It can be kept any size you want for as long as you want. Evergreen and beautiful year around and does not require summer water"once established". Al

I recommend starting with the largest size you can afford. I went through a conifer phase, especially liking the fastigiate ones and ultimately ended up getting rid of some really nice plants including skyrocket junipers, arborvitaes(Degroots Spire is a nice narrow one) and yews because they grow so slowly and would have taken a few more years to make even slightly the impact I wanted.

'Tiny Tower' Italian Cypress. It will get taller than 10' but will do so so slowly it may not be a problem.

Korean fir!