Thin Mini ITX is specifically created for OEM use in All-In-One computers. Theoretically, standardizing it was supposed to make it easier for OEMs to quickly iterate on designs and for end-users to be assured they have replacements, but it didn't really take off. While there was a surge in designs following the standard a couple years ago, everyone has mostly gone back to fully custom solutions, and consumer grade AIO chassis are just a giant M-ATX/M-ITX box at the back of a monitor.Ok maybe enthusiast was here the wrong word. What we have on the thin-ITX board market looks like oem stuff. Not very special and every board looks nearly the same. For myself it isn't a problem, but many users buy hardware also because of the look. E.g. the Special OC, Extreme or Maximum edition of the boards.
As far as including a GPU on a Thin Mini-ITX, board, I think MXM makes much more sense given the form factor it's designed for and meshes better with how it works (Thin Mini-ITX boards have mandatory LVDS and a pre-defined location for an optional eDP port specifically to drive a monitor inside the same chassis, and MXM is specifically designed to be able to output to LVDS and eDP having dedicated signal paths for them rather than using PCIe.
That's designed to be used as a DIY firewall/server merged with a router/switch if I am not mistaken. It has specific add-in boards with 2-4 Ethernet ports among other things (I think the options are an NIC or a RAID board, but I haven't looked at it in a bit).Huh, you're right. There's really not many Socket 1151 Thin ITX boards available. I did find this gem though with a side mounted PCIe x4:
http://www.jetwaycomputer.com/NF592.html
The chipset and other features aren't likely to mesh well with a gaming sort of build.