PCIe Expansion into Media Bay

[MP39]

With so many people not using DVD Media Bays as much on their Mac Pros and looking to expand HDD/SSD storage etc., I was curious if there was a solution that exists out there to expand PCIe bays into the media bay?

I realize there are external chassis solutions available, but they all seem to be a 2-lane expansion solution to modest 2-lane PCIe card storage at quite a price.

Has anyone ever tried this or customized a solution for their PCIe cards in this area to optimize usage?