How high-end are we talking about? Do you know off-hand of any models supporting this?

I haven't seen such features on boards under 200 EUR, from Asus, Asrock and Gigabyte.

The thing is, if I have to splurge for some 400 EUR "gaming" model, I might as well move to a "workstation" CPU supporting more lanes out of the box, and the mobo will be priced roughly the same.