Frist, define "unique".
Second, 15 ft. high-there are many shrubs that easily get that tall and with some limbing up will have a "tree" shape.
Third, I'm confused on the "part to full shade along with hot temperatures and down to zero degrees in winter" bit. Can you narrow it down? You're on the east side of the Sandias so what exposure will these plants get?
How far up the mountains are you located? Zone 5/6-is that the USDA zones? You must be up aways.
What's your soil?
"Branches start up a little higher", higher than what?
"Three trees on either side of the door for a total of...", how much bed length in front of your house do you have?
The "horrific looking juniper bush", are they landscape junipers or native?
"Draw the eye upward", 15 ft. isn't going to draw eyes upward very far.Do you want to draw eyes or balance the plantings with the height of the house?
"The bed is several feet from the foundation", how far? 10? 12? You don't want a tree closer that 10-12 feet to your house. Trees need a lot of space and remember, what goes up, will come down and perhaps on your roof. Also, snow load sliding off of limbs needs to be kept in mind, especially at your front door.
I keep thinking that some large limbed up shrubs would work nicely for you especially that close to the house and without knowing the bed size. Do you want evergreen or deciduous plants?
There are some great nurseries in Alb., have you talked to any of them?