TV Shows On DVD has the official announcement of the Looney Tunes Golden Collection Volume 4, though not the official list of the cartoons that will be included.
Disc 1 is Bugs Bunny; disc 2 is a collection of cartoons by Frank Tashlin, disc 3 is a Speedy Gonzales collection (which may, unfortunately, include some of those post-1964 Daffy/Speedy shorts), and disc 4 is assorted cartoons about cats -- Sylvester, Pussyfoot, and other WB cat characters.
I have no great love for Speedy Gonzales -- though Bob McKimson's "Tabasco Road" is a great cartoon, and I also like Friz Freleng's "Mexicali Schmoes" and Speedy's debut cartoon, "Cat-Tails For Two" (McKimson). In general Speedy works best when the focus is on other characters (in "Tabasco Road" most of the fun comes from Speedy's two drunken pals; in "Schmoes" it's the two dumb cats). When he's a Mighty Mouse type hero, zooming in to save hungry mice from el pussygato Sylvester, things can get dull; and that, unfortunately, is the formula that most Speedy cartoons follow.
Speaking of Speedy: as you may know, while Speedy was created by McKimson, Speedy's second cartoon, "Speedy Gonzales," was directed by Freleng, who re-launched the character with a new design, a new formula, a different adversary (Sylvester). It was one of those cartoons that's clearly a "pilot" cartoon, made in the hopes of launching a series, which it did. And it won an Academy Award.
What's interesting is that the first three WB theatrical cartoons to win Academy Awards all fall into that category: cartoons made to re-launch established characters in a series. These three cartoons were "Tweety Pie" (1947, the first teaming of Tweety and Sylvester), "For Scent-imental Reasons" (1949, re-launching Pepe Le Pew) and "Speedy Gonzales." I would take a guess that whenever there was a cartoon that WB was counting on to launch a series, they would promote that cartoon extra hard for an Oscar, since the Oscars undoubtedly helped these three series get off the ground.