Whew, good thing I did a last second double check, I was JUST about to post this.
My notes have some other details from the panel...
- Dave Filoni (Star Wars: The Clone Wars and Star Wars Rebels series director) did most of the talking, though Simon Kinberg and Greg Weisman appeared via holocr-- I mean a video presentation. Warwick Davis was also there.
- Filoni also showed concept art for an astromech and protocol droid
- Art style will be different from Clone Wars, as mentioned, they were going for a Ralph McQuarrie look, something more illustrative
- Character design also influenced by Hayao Miyazaki
- During Q&A, Filioni did not directly answer a question about continuing storylines from Star Wars: The Clone Wars, but did say "I love all Star Wars characters, especially the ones I created"
- Scheduled to premiere in fall 2014 as a one-hour special telecast on Disney Channel, and will be followed by a series on Disney XD channels around the world.
My article source: Star Wars Celebration Europe 2013: Star Wars Rebels Logo, Art, and Details Revealed
Also some info from the blog: http://starwarsblog.starwars.com/index.php/2013/07/27/swce-2013-star-wars-rebels-panel-with-dave-filoni-liveblog/