SATA allows only one drive per port. Your best bet for a large storage array is probably to buy a RAID card. SATA "port multipliers" are available but channeling multiple drives through one SATA connection could cause a bottleneck.
Even if you go with 1.5TB drives (They are cheaper per GB than 2.0 TB units), you can still get 12 GB in a mobo with 8 SATA ports. How much space do you need? If it is more than that, consider an NAS case that will hold many more drives and simply attach as another network device. Or even more than one NAS case. By the way, once you get to about 20 drives you may run out of letter names.