Asus Z97I-PLUS Mini ITX LGA1150 Motherboard (Z97I-PLUS) - PCPartPicker
While the mini-itx form does limit multiple GPUs, amount of RAM, number of fan headers, SATA drives, and so on, this mobo is very well made and does feature a M.2 slot (albeit hidden on the rear of the board, requiring a full removal should I ever go down...