Common knowledge tells us that using the Intel SATA 6Gb/s over alternative (Marvell) controllers is the way to go for 2x RAID0, I've not seen any benchmarking that gives us a definitive answer.
Also there seems to be very few onboard choices for those of us that considering 3-4 SSDs in RAID. The Asrock X79 Extreme9 touts 4x RAID (1/0) via the Marvell 9172 controller. I've been told that this is poor choice for SSDs as they don't have the throughput to prevent bottlenecks, but again trying to find benchmarks on this has proved challenging to say the least.
With SSD prices dropping, and people trying to maximize peformance I think it'd be a great article showing people what solutions are available and how they stack up against one another for both 2x and 4x RAID0 onboard configurations, you could also compare these results to the results of the discrete solutions that have already been documented.
The problem is that it is really just an academic exercise. I've run one Vertex 3 240 and a pair in RAID zero. While my benchmark numbers were higher for the RAID 0, subjectively I felt no difference between the two for a few hours of the usual things that I do including office stuff, VMWare, video transcoding. I was actually a bit disappointed. This was a much different experience than when I first tested 4 raptors in RAID 0 and found them feeling very quick.