SATA-III ports have been around since the introduction of the Sandy Bridge chipset, for both desktop and mobile chipsets. It's just up to the individual laptop manufacturers to enable support for it in their respective products.
From Intel's website
, they are supported on laptops with the QM67
, and HM67
chipset (which covers nearly all modern Sandy Bridge laptops) and newer ones too.
From the From the Intel 6-Series Chipset datasheet
, these chipsets have support for SATA-III devices on two PCH (platform controller hub) ports (0 and 1). It is up to the laptop manufacturer to include more then those two (up to six in total), given the following caveat:
The PCH has two integrated SATA host controllers that support independent DMA operation on up to six ports and supports data transfer rates of up to 6.0 Gb/s (600 MB/s) on up to two ports while all ports support rates up to 3.0 Gb/s (300 MB/s) and up to 1.5 Gb/s (150 MB/s). [...] PCH supports the Serial ATA Specification, Revision 3.0.
It is worth mentioning that no laptop currently supports SATA-III externally (e.g. through eSATA). The latest Intel chipset only supports SATA-II for external SATA devices (again, see the datasheet
for more details).