Rack mount case with GPU support bracket

[Esava]

Hello guys, 

I have to build several rack mounted systems which will be moved around. 
They don't need huge amounts of drive slots (the systems will only have SSDs in them) and will only have one GPU inside. 
But this GPU is the problem. I am kinda scared that when these systems will be moved (most of them will be mounted in television broadcasting vans) that the GPUs will break from their slots. 
Are there any 4U (or preferably even smaller but 4U would be fine) cases that have inbuilt GPU stability support (in bracket form or some other way)?
The GPUs in question are also quite big/heavy (2080S and in the future 3080 and maybe 3090s) so even in a normal desktop case they could need some support stopping them from "sacking". 

If there aren't any such rack cases out there does anyone have an idea for the GPU support short of manufacturing custom mounting hardware?
We are a very small, independent camera development company so all suggestions are greatly appreciated. 


Thanks for your time and I hope you all have an awesome day.