DELL R410 two x8 PCI-e cards in one Gen 2 x16 slot

Has anyone done this? Is there any hardware out there that can do it?

I need to add a 10 Gig card and an HBA to a Dell R410 which has one Gen 2 PCI-e x16 slot. I don’t mind throwing them somewhere in the chassis.
Intel says PCI-e bifurcation is supported on the 5500 chipset:


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Thoughts?