Finally got around to updating the OP.
I did all my testing and some photography, and sent a few prototypes to some friends to play around with and gather feedback. Everything seems to fit, although mounting the GPU is difficult. The mounting flange gets in the way of the screwdriver so installing the gpu is cumbersome. though definitely doable.
Some pics of the different layouts:
Next steps are to optimize the design a little bit so its easier to work with.
My main 2 things id like to change right now:
1) GPU mounting. Need to make installing the GPU easier. Probably going to optimize a flange away.
2) Nicer dimensions. In the traditional layout, there is no reason i cant make it also be nice whole mm dimensions, so il try to optimize that in.
There was also some feedback from reddit regarding a low profile gpu bracket. strongly considering that.