You can never have too many PCIe slots, or too much RAM, I say. Supermicro seems to agree, and proffers their latest quad-Xeon monster motherboard in response: the X10QBi:
Supermicro | Products | SuperServer | 4U | 4048B-TRFT
This beast, which of course requires a custom Supermicro chassis, features quad Xeon E7 CPUs that'll cost you the same as a small car and - here's the impressive part - 96 DIMM slots and 11 PCIe 3 slots. All of a sudden my quad Xeon E5 database...
My new favorite over-the-top motherboard: Supermicro with 96 DIMM slots
Supermicro | Products | SuperServer | 4U | 4048B-TRFT
This beast, which of course requires a custom Supermicro chassis, features quad Xeon E7 CPUs that'll cost you the same as a small car and - here's the impressive part - 96 DIMM slots and 11 PCIe 3 slots. All of a sudden my quad Xeon E5 database...
My new favorite over-the-top motherboard: Supermicro with 96 DIMM slots