I was under the impression that the Xorro slot was behind and in-line with a x1 PCI-Express slot, so you can ignore Xorro and plug in a standard x1 PCI-Express card. There's nothing b0rked about it being a PCI-Express slot.
funny thing is: there is a slot but there is no cards for it. not even mentioned, not even announced (we are good at it, right?) not even questions asked. and even more funny is that the slot is standard form factor that can easily be confused with another widely used standard. so what happens if a dumbnut puts a pcie card into that slot? does warranty covers that, i wonder?