I would count on 6Gbps SATA. All of AMD's chipsets in manufacturing since mid-2010 have 6Gbps SATA.
Also a look at the Fusion platform shows that they work with a new south-bridge - "Hudson FCH" which is an evolution of last year AMD's latest chipset - SB850.
Very similar notebook by HP was reviewed by AnandTech: http://www.anandtech.com/show/4187/hp-dm1z-taking-fusion-on-the-road . It confirms Fusion is coupled with Hudson FCH.
Reference for all AMD chipsets and their comparative features can be found here: https://secure.wikimedia.org/wikipedia/en/wiki/Comparison_of_AMD_chipsets .
That said, I would not rush to get a 6Gbps SATA SSD. Most if not all of them are built with 25nm NAND flash which is known to have drastically lower life than 34nm due to the lower process node and high voltage needed to program the cells. The newer SandForce 2xxx controllers use stronger ECC correction in order to cope with errors introduced by this NAND flash. If I were you I would get a 34nm NAND based SSD with SandForce 1xxx controller. A quick example is OCZ Vertex 2 with model numbers OCZSSD2-2VTX*G where * denotes the capacity. There is another series of the same SSD - the "E" series with model numbers OCZSSD2-2VTXE*G. These series use less space for over-provisioning and some are known to use the newer 25nm NAND flash. Both are available in the retail chain today. Of course these SSDs are also cheaper than the 6Gbps SandForce 2 based ones and only about twice slower. That said they are magnitudes faster than HDD in the dreaded random reads/writes so the speed doubling becomes more of a marginal difference than a ground-breaking must-have feature.
If you need a reference for the performance of these drives I have two Disk Utility benchmark shots of a very similar drive here: http://lightrush.ndoytchev.com/random-1/howtoconfigureext4toenabletrimforssdsonubuntu . One is after a month of use, the other is after several. The drive tested uses virtually the same SandForce controller as the OCZ Vertex 2.
In case you are wondering why am I talking about SandForce based drives only - it is because they are better than anything else in power consumption and equal or better than anything else in performance - http://www.anandtech.com/show/3681/oczs-vertex-2-special-sauce-sf1200-reviewed/3 .
Lastly - there is some problem in eCryptfs that limits the maximum speed of sequential reads/writes which makes SSDs as slow as HDDs in those operations over an encrypted Home directory.