Dutch Bros? I've never heard of it. You say it's popular in the PNW? Maybe there isn't one in Washington.
Edit: Just looked it up and there's one in Renton, Tacoma, and Everett. I haven't been to one because I never go very much farther south or north if I can help it. Most of my friends live in Everett, though. Maybe they've been to it. I will go try it next time I hang out in Everett!
That's an awesome idea, btw! β€οΈ I feel like I've thought about something similar before too.