According to the newsletter they are still thinking it is either polygenic or dominant with incomplete or variable penetrance. I think, if anything, they are leaning towards the dominant with incomplete or variable penetrance mode of inheritance as the basic route with the possibility of another gene being involved as well--since they went into more detailed explanation of that.
If it is all dominant or mainly dominant it should be much easier to find a marker. At least we can hope so.
I emailed Penny Knowler and she is guessing about 3 years to get the gene results.