Not one that covers back seats folded down. But I have this
MidWest Pet Barrier Wire Mesh Car Barrier
https://www.amazon.com/dp/ (commissions earned)
And this
Cargo Liner, Alfheim Dog Cargo Liner for SUV, Universal Fit for Any Animal. Durable Liner Covers and Protects Your Vehicle
https://www.amazon.com/dp/ (commissions earned)
And then just last week got the Mazda OEM rubber cargo liner to go on top of the amazon liner.
Works great, I highly recommend the rubber liner as it's grippy and it covers the side pocket areas near the hatch, and makes it way easier to clean hair.
Throw a doggy bed from Costco on top, and you're good to go.
I have two dogs, a big lab/mastiff mix and corgi mix, and they both fit in the cargo area with rear seats up.
EDIT: now that I think of it, you can use the amazon one I linked above with the rear seats down.. since it it straps to the headrests and covers the whole back of back seats. Didn't think about that till now, I'll have to try it sometime and move the barrier closer to the front seats to give the doggos some more room.