You might want to check out the older GM mid-size guys - Buick Enclave, Chevy Traverse, GMC Acadia. Last time I looked they were flat-towable, but that was before the new 9 speed transmissions.
Be aware that the 2017 and later Acadia is smaller than the others and I have not tested the rear seat accommodations in that vehicle.
The 2018 Traverse and Enclave are actually slightly BIGGER than their predecessors.
EDIT - Ooops, just checked the 2018 Traverse manual - NOT flat towable. My 2016 Acadia was. Must be that new 9-speed transmission.