I understand now, but IMO that would make for a pretty awkward case, with the back of the GPU at the front of the case. I can't see it being very appealing without at least a cover, but then you've still got a video cable exiting the front...I think it should be possible to make a PCIe riser that allows the motherboard and gpu to be placed back to back, but have the connector of the GPU still be on the bottom, meaning the riser does not have to be so big. This of course also means having the connector of the GPU in the front of the case (something I forgot to mention), which might be a feature allowing you to call the case "VR ready" .
There's only so much you can do. Fans with a higher thickness to diameter ratio generally are able to generate more air pressure, and GPU fans are thinner out of necessity. They already have to push air through the restriction of the GPU heatsink, and then make a right angle as they hit the PCB, so they're already being asked to do a lot. Filters just make it that much worse.Do fans on GPU's really have that much more trouble overcoming airflow restrictions from dust filters compared to regular case fans? I would think the way the fans are directly placed on the GPU heatsink would make them fairly pressure optimized.
I agree that heat is a potential issue, which is another reason I favor the front-to-back layout that I've shown rather than a back-to-back layout.Placing the mobo and the GPU back to back seems cool, but wouldn't this limit M.2 support on most ITX boards if I'm imagining this correctly? Yea, you could put it on beforehand, but I feel like heat would be a big issue, especially given that most of them aren't great at that anyway.