Love to see Gossamer Gear Mariposa. I would think they would be willing to make a deal if they have guaranteed orders ready to go. Massdrop could pair it with a Granite Gear pack cover or Sawyer bladder/filter combo.
I tried on the Zpacks Arc Blast, Gossamer Gear Gorilla and Mariposa, and I have the Exos 58L. All were tested with 25 lbs and with a bear canister. I thought the Mariposa was the most comfortable especially with over 20lbs, most adaptable and gives potential to do neat things like switch out the backpad for an airpad, or stuff your tent in the long side pocket, or put your stove on the upper side pocket. The Zpacks is good for under 20lbs carrying weight. I thought the air mesh back was not as good as the Exos. I say the Zpacks and MLD are for ultralight backpackers who keep their weight really really low.
I'm actually wanting the gorilla. The mariposa is a through-hiker pack and I'm wanting something a little less substantial. Their packs are sold the moment they list them on their site though so I doubt they will cut a deal. Just.like.the Osprey packs.