NSG S0, once out, will most likely be the go-to case for such setups. Until then, an HDPLEX H5 is cool.
My desk has a H5 on it, housing an i7 8700 (non-K) and a GTX 1060. The TIM under the heatspreader is replaced with Thermal Grizzly Conductonaut and Thermal Grizzly Kryonaut is used as every other TIM that the case setup needs. The CPU is on stock clocks with a voltage offset of -30 mV. The GPU has the power target reduced to 90% and clocks increased by 130 MHz, so that it is effectively undervolted as well. The PSU is a Seasonic Ultra Prime Titanium 650. Prime95 with AVX throttles really, really fast, under a minute, perhaps, but is a very unrealistic load. Non-AVX stress tests and FurMark take a while to start throttling (20 minutes?), as the thermal capacity of the aluminum case is quite big. After hours of gaming, the GPU and CPU float around 80 C while providing full stock performance. I don't do 3D rendering (other than in-game) or video en/decoding, so have not had long, real-world, full loads to see how temperatures behave with those.
From the discussion I've had and forums I've read, I think that people are afraid of putting more power in passive cases and having their components at "high" temperatures, despite those being rated for them.