I'm about 99.99% sure that Ahsoka will be featured in Star Wars Rebels in some capacity. Same writers, she's alive, it's pretty inevitable. I'm just hoping it's a cool story. My personal hope is that we'll meet her early on but we won't know it's her... we'll get a few subtle clues and maybe a season or two in we'll get a shocking revelation. If you're a fan of Marble Hornets, I'm hoping Ahsoka we'll be a bit like the Hoody character, basically a cryptic, somewhat threatening but also strangely helpful masked figure who is later revealed to be an old friend.
TO THAT END... here is Ahsoka's disguise in my little fan fix in progress, in which she'll team up with Rex, who now knows Fives was telling the truth about the inhibitor chips and removed his and went awol (the way his character arc was heading anyway I'm pretty sure), and of course Lux as a little team trying to investigate how Order 66 was orchestrated. And of course she's aged since Clone Wars so I tried to make her look like the vision in the Mortis arc as an adult. Thank you Shaak Ti for donating your lekku.