Gigabyte has managed to shrink the GTX 1080 card to micro ITX standards. The new GTX 1080 Mini ITX 8G card retains the reference card clocks and 8 GB VRAM memory, adding only a dual slot single fan cooling system.
https://www.notebookcheck.net/Gigabyte-announces-the-GeForce-GTX-1080-Mini-ITX-8G-for-small-form-factor-PCs.246278.0.html