The TUF Sabertooth X99 is a Socket 2011-3 beast with eight DDR4 slots (DDR4-2400) which can accommodate up to 64 gigs of UDIMM. The board ships with three PCIe 3.0 slots and a couple of PCIe 2.0 slots.
In terms of storage you get 10 SATA 6Gbps plugs, two SATA Express 10Gbps ports and an M.2 32Gbps slot.
As far as connectors go, the TUF Sabertooth X99 features pretty much everything you could wish for, including more than a dozen USB ports (8 of which are USB 3.0), Thunderbolt AIC, dual gigabit LAN and the standard array of multimedia outputs and inputs. The board also has two USB 3.1 ports.
It’s unclear when the TUF will actually ship, but you can pre-order it on overclockers.co.uk. The price is 299 GBP (incl. VAT).