After 25 revisions and numerous PLA test prints I have finalized my design of these modified rails for the popular NZXT H1 that allow you to rotate your case internally by 90°
To install just remove the screws under the rubber caps in the original plastic rails and print these in PETG or another high temp material, suddenly you'll have an amazing case that shows off the front of your graphics card instead of the side.
With these attached the side metal sheet goes on a little differently, because there's a metal blockate about 3/4 of the way down the guide rail portion is actually an open keyed slot, you put the metal sheet sides on more broadly at first and then snap them into the channel towards the bottom. After putting it on and taking it off a few times it gets easier.
The small slots in the sides are for optional neodynium magnets (3/4 Inch) which help the rails retain the metallic front and rear panels, and are sometimes required for front panels you may wind up ordering off of GhostSheets etc.
I plan on making an H1 disassembly video to show exactly how this was installed, presently it requires some trial and error regarding the rotation of the frame. Please have a rotary tool like a Dremel with a metal cutting wheel to shave little bits off of where the top meets with the vertical metal bars as these may not fit together perfectly when rotated.