Feels like it'd just create a market for a big rack-mountable multi-bay PCIe enclosure, with its own internal power supply, that you could connect with one ore more thunderbolt cable. I don't see any reason why a solution built around a Mac Studio should have to be significantly more cluttered.

I don't know if such a solution exists right now, but I'm thinking there's a fair chance it will soon as the Mac Pro disappearing creates a demand for something like it.