So while w360's been plugging away at his version of the PCX design, I've been doing a bit of ideating on various concepts, and today came up with this:
Basically similar to the original design, but widened to allow the flexATX PSU to be rotated, and shortened (depthwise) accordingly. The two slim 120mm fans would be replaced by a single 140x25mm intake fan, with the possibility of two 80mm exhaust fans at the top.
Hypothetical specs
Dimensions (H x W x D): 340 x 94 x 240mm, 7.7L
CPU cooler: 40mm (exclusive of intake fan)
GPU: ~215mm long, ~125mm tall
PSU: flexATX @ 150mm long
Fans: 140x25mm intake, 2x80mm exhaust
Drives: 2x2.5"
Essentially, it's a small footprint case designed around showing off a card like the Zotac GTX 1080 Ti. Unlike the original PCX design, this is less of a console-style case, as it's meant only for vertical orientation and lacks ODD support.
My feeling is quite a few people would be more interested in something like this vs. the original design, but I'm curious to hear people's thoughts on it.