- The machine is built around the Asus B150M PIO. I have one incoming probably the next week. This makes a riser unnecessary.
- Since the motherboard is already 203.2mm (eight inches) long nothing much is lost by making the case 211mm long so that the Zotac Mini cards fit. The video card area needs to be about 12-12.5cm wide for PCIe connectors / Gigabyte 1070 Mini. It's enough. Don't forget the actual PCIe edge connector is over the motherboard. This sets the height of the case, the video card is about 40mm high and starts about 10mm high.
- Hopefully 7mm thin disks fit below the GPU. While 211mm would indicate three fitting, we need the space to run power cables so two. Seagate has a 7mm 2TB unit and of course all SSDs are 7mm. Two ought to be enough.
- Next to the video card, a SeaSonic SS-350M1U. It's longer than your ordinary Flex ATX but it could be pushed out so it starts at the end of the video card PCI flange. This adds about 1.5cm or so which is badly necessary for the cables. I have several reasons to pick this particular PSU: zero fan mode until about 150W. Two, as the disassembly shows, no heat sink covers it. So an alternate cover could be made from a material like http://www.ledsupply.com/images/products/12v-of-xxa.jpg this and then two 10mm thin 80mm fans could be attached to the case cover just above the PSU providing a ton of quiet cooling capacity ( I would let the user install the custom cover and unplug the factory fan...). Three, it's modular and it shouldn't be that hard to get a custom harness made. Perhaps this company? Or the famous Kareon Cables, we could have low profile PCIe connectors.. But this is just a small detail Anyways, a custom harness would make the case extremely neat, all the power cables running to or under the video card, barely surfacing to plug into the ATX and P4 port. I would add two 8 pins so the 1080 Ti Mini can run. It's only 250W. The CPU is only 65W up to the 7700. So the power envelope fits.
- A 1U CPU cooler is 27mm. The Prolimatech Ultra Sleek Vortex 14 is 13mm. That makes it 40mm. The video card is 40mm as well. So hopefully this fits. So leave a 105 x 105 fan spacing on the case cover so that the fan attaches to the case cover and covers the CPU socket completely. That's quite a bit of quiet cooling -- even the 7700K is doable if you are not running a 1080 Ti (or limiting it with the MSI Afterburner). If my screen-based measurements are correct, a 140mm fan would also cover the m.2 which is just plain great.
- Nothing on the front cover. It's all passive air intake.
- On the back, where the DIMM slots are, fitting a power switch should be easy. Between the PS2 and the Ethernet, I would add two wifi antennas. That's where the wifi card would be anyways in the mPCIe socket. I suspect even that's what that empty space is for in the first place.
I would love to have partners in crime to help realizing this, I can provide some funds towards a prototype and such.