ASRock has connected 22 SSDs to a single motherboard, the Z87-Extreme11/ac.
To make a point, ASRock has decided to fully populate all of the storage connectors on its new Z87-Extreme11/ac motherboard. To do this, it has used a grand total of 22 Plextor M5 Pro SSDs. Six of these SSDs are connected through a SATA3 interface (standard on the Z87 chipset); 16 of them are connected through an SAS3 interface. Unfortunately, ASRock didn't configure the drives in any form of useful RAID array, so it was impossible to figure out any performance numbers.
Of course, just using 22 SSDs alone isn't enough. How could it be? On top of this, ASRock also connected four Radeon HD 7970's, filled up all the memory banks, and connected its own Wi-SD box. The Wi-SD box acts as the motherboard's WiFi and Bluetooth Antenna, has two USB 3.0 ports and a multi-card reader.
Let's not begin to imagine the sheer cost of this kind of setup.