ASRock have done something very impressive, created a mini-ITX X299 motherboard.
The tight confines of this board have not stopped them from including numerous features. There are dual Intel NICs in addition to dual band 2.4/5GHz 802.11ac WiFi connectivity on this board. USB3.1 Gen2 Type A and C connectors are found on the back along with four USB 3.1 Gen 1; the audio outputs include optical, the Realtek ALC1220 behind them supports 7.1 audio.
ASRock fit three M.2 slots on this board, one on the front running along the back panel that supports both PCIe and SATA and another two PCIe 3.0 4x hidden on the back. There are an additional six SATA 6Gb/s ports for more traditional storage. The motherboard supports quad-channel memory of up to 64GB of DDR4-4000, with DIMM slots above and below the CPU socket. The single PCIe 3.0 16x slot is at the very bottom, with strong reinforcement to hold up a GPU that will outweigh the rest of the system.
You could choose to try to cool this with a standard cooler, but that is not your only choice. ASRock worked with Bitspower to create a custom waterblock as you can see above. That will ensure a perfect fit as well as proper cooling.