According to this, Imperial Armour 16 will have the Red Scorpions with Ad Mech allies fighting against the Tau. There are some pics as well, but I had a hard time re-sizing them off of facebook, but you can see them at the link.
via Mark Tait on Facebook -Warhammer 40K: Tau Empire
So, i am happy to report that as i brought to you all last summer, a new FW campaign book is being released early summer 2016!:-D
Featuring Kel'shan sept ( notice the yellow markings) facing off against skitarri and Red scorpians.. Also pics of the new(ish) display board:-D
Marc Chong from the 40k for Adults group posted this, as well.