RAM definitely do an iPad mini 4 kit:
RAM iPad Mini 4 Suction Cup Mount Kit - from Sporty's Pilot Shop
so I would expect you could find a supplier here. Have you rung Transair to discuss?
(I'm assuming it is a different size to iPad mini 3, and this isn't just a question of missing information on the Transair page?)
(edited to add: RAM is the way to go, excellent quality kit)