Update: I got my first S700 prototype in today. Actually, I got two and so far it looks really nice. I'm more excited about this case than I am the S401. Below are some pictures (albeit bad ones, taken with phone) but expect some better pictures taken with my good camera soon.
That is a Threadripper 1950X on an ASRock ATX mainboard and a Vega 64 LE. The radiator is 360mm x 35mm with 3 x 120mm fans. I've got 4 or 5 different reservoirs and pumps to test fit, but this first prototype is almost good enough to actually have a running system in. One problem is that the machine shop didn't put the right standoffs on the mainboard so it sits really close to the case and the idea was that the PCIe extender would be sandwiched in between those to keep things tidy. I still have to order the PCIe extender with the correct length cable to actually test this setup.
Note that large empty slot in the back. The idea is to support adding an additional SFX/L PSU, PCIe device(s), disk drives, etc. If this case is actually produced for sale, I'll have to offer a few standard options. I'll be using it as either a reservoir mount or a second SFX/L PSU.