TVshowsonDVD.com have been reporting rumors of other future DVD sets from Warner Home Video for 2008.
Freakazoid seems to be on the minds of Warner executives for a possible release...
http://tvshowsondvd.com/news/Freakazoid-Rumors/8383
Tiny Toon Adventures has been mentioned in a Warner Bros Animation info site as:
"There currently are no plans for the final, volume 4 DVD release of Animaniacs. However, Tiny Toon Adventures has been green-lighted for release, in the same numerical-order format."
http://tvshowsondvd.com/news/Tiny-Toon-Adventures-Rumors/8384
I wonder if Warners is considering future sets of Taz-Mania, Sylvester and Tweety Mysteries, Histeria! and Pinky Elmyra and the Brain?