What is "SATA 6"?
I thought, that the upcoming SATA standard is SATA 3.
Yes, I believe it is SATA 3 but commonly referred to as SATA 6 (6 Gbps/s Third generation)
I doubt, that you will get an answer here.
There are only a few Intel X25-M G2 SSD owners, who are running 2 of them as RAID0. It would be a surprise for me, if anyone of them has already a mainboard, ehich supports SATA 3.
As far as I know there is no big advantage to use an Areca Controller with Postville SSD's on usual mainboards, which just support the SATA 2 standard.
By the way: My Intel ICH10R system, which is running with 2x160 GB X25-M G2 SSD's, is extremely fast (up to 570 MB/sec read speeds) and I don't see any reason for buying a new system.