This is pretty brilliant:
The same company also makes a 1U rack mount for a Mac Mini that-
Seems to me a great solution if you're looking to upgrade to a new Mac that doesn't come with PCI card slots - video/audio pros come immediately to mind. ProTools HD users with existing PCIe Core/Accel cards wouldn't have to trade in for a Thunderbolt Native interface. Seems like a great idea to me.
See the products on Sonnet's website: