While we still don't have any official confirmation on the 7th season yet, we do have a new voice actress joining the pony family as a whole. Janyse Jaud, an actress involved in Ed Edd n Eddy, Inuyasha, Marvel, as Pinkie Pie in the direct to video 'Twinkle Wish Adventure' and more will be voicing a new pony according to her Twitter page.
Fingers crossed it some season 7! As far as I have seen, most of the voice acting announcements have already happened for the movie. It could very well be a late addition to the cast over there though.
Thanks to Feather Data for the heads up.