Too what end?
What is the intent of this response? Are you doing similar research?
Here's some of my faves:
Miles Davis Gil Evans, My Ship, Lament and Maids of Cadiz from the Miles Ahead Album.
Concerto de Aranjuez from Sketches of Spain
Gil Evans - Round Midnight (From "New Bottle, Old Wine", also on "The Complete Pacific Jazz Sessions")
Johnny Hodges with Ellington Orchestra - "I Got It Bad and That Ain't Good", "Prelude To A Kiss", And Isfahan (from Far East Suite) is one of my top ten favorite songs.
Harry Carney with Ellington - "Sophisticated Lady."
Sugar Rum Cherry (From Ellington Suites) has a nice vibe to it, not quite a ballad, probably works better as a slow opium-ed up foxtrot.
Lush Life is probably my favorite ballad, the Phil Wilson arrangement of that is pretty tight if you want a big band arrangement, but the best recording of that in my opinion is the John Coltrane with Johnny Hartman (which is The Quartet with JH providing vocals.)
That Maynard Arrangement of Stella By Starlight I was trying to think of is Phil Gray on trombone.
I'm sure I'll think of some others...