I'm often asked whether "[Studio]/[Movie]" still does iTunes Digital Copy or not anymore. Some answers are cut and dry, and others are not. I will update/addend this piece over time.

ONLY UltraViolet

Sony
Warner Bros./DC
Fox Searchlight (as of Summer 2013)
NBC/Universal/USA/Syfy TV

Depending on the title, the UV code may or may not redeem for HD.

BOTH iTunes + Ultraviolet

20th Century Fox & Fox Animation
Universal (movies only)
Paramount (new release only)
Lionsgate/Summit

Recent releases have seen the iTunes codes redeem for the HD versions of movies (Paramount sequels seem to deliver as double features of late). UltraViolet codes redeem for SD only unless otherwise marked.

Digital Copy Plus (Choose One: Vudu/Amazon/iTunes)

Disney/Pixar/Touchstone/Marvel

You get to choose from the services it offers you when you redeem the code. Sometimes it's all three (Oz the Great and Powerful), but I've found that sometimes, you don't get iTunes as an option (The Many Adventures of Winnie the Pooh ). Note that Vudu equals UltraViolet.

iTunes includes Extras

Pixar
Disney Classics Diamond Editions (starting with The Little Mermaid)
Paramount (new release only)
Lionsgate/Summit
some pre-Fall 2013 Universal (new release only)

All of the above is why I make my own digital copies from Blu-rays when there's no iTunes code.

UPDATE 4 November 2013: Added above, a breakdown of iTunes Digital Copy studios that include iTunes Extras.