I have found Dunkin Donuts Iced coffee,and better than McD's!! McD's is how I got started drinking any coffee hot or cold.
Sad thing DD just recently discontinued their 99 cent Iced coffees after 3PM. If you join their DDperks program you can get 99 cent dark roast for another 30 days. earn points earn free drinks etc..
My favorite flavors: Rocky Road and Oreo.
For our Home brewed Iced coffee we start by using "cold brew" coffee extract, then we add sweetened condensed milk, our flavor syrups, then the rest we fill with skim milk.
Pioneer woman has a recipe on her site.
Glad I am not the only one who devours Iced coffee and Choc. chip frappes!