I can find plenty for the S5, but not the S5 Active. Spoke with Samsung, and they are working to come out with a charger cover near the holidays, but I'd settle for a non-Samsung product if it works.
I'm pretty sure that there are no contacts necessary for a Qi (or touchstone) receiver. I would love to be wrong on this. All of the pictures that I have seen of the inside back of the Active show no contacts.
It really would benefit from Qi - as you would never need to open the USB flap.