ASRock was the first to respond. They have tested the Phenom 9850 on it's A780FullDisplayPort mainboard and it has worked well on it. They also send in their Screen shot showing the 9850 CPU-Z to prove it.
Jetway also send in their concerns about the PA78GT mainboard. They claimed that they have tested the 9850 on A06 BIOS for the mainboard. It has gone through 3Dmark tests without issues. They also said that another model featuring SIdeport memory, HA06 also support the 9850. Both models did not indicate they support Phenom 9850 on it's website.
As for Gigabyte, they are looking into the matter. J&W (as written on Anantehc), they will be having a new board. ECS on the other hand claims that their board will work with < 89W processors.
Some have told me that 790GX or 790FX will officially support the Phenom 9850. They do not think that many will buy a high end CPU and pair it up with a low end chipset mainboard. Even if it works, it is probably unofficially supported.