Give me full ATX with 15 sata ports and I would bite. 10 HDD and 5 caching ssds. I would prefer full axt because with that many drives I would need a full case so might as well use a full board.
Few years ago I had a board with 10, can't find any boards with that many anymore. Ended up with one with 8 plus two expansion cards to get me to the 13 drives I have currently with 3 spare for future expansion. Replacing my old 4TB drives with 12TB drives as my media hoard expands. Upgrade feature of radarr has been a blight on my storage. 😀