Hello Gregg,
Because I'm on a MAC, for some reason my PM doesn't work. It may be a MAC security issue. For now this is the best way to communicate.
Remember, I won't have any 906 answers until late this fall. As for the 917(s), the standard 917 is ready for sale. However, there is a one year wait on these right now. The 917K (Martini finned version) and 917/30 (CanAm) are still in development and are due next spring.
The 906, 917(s) will except any 911 motor or if you happened to have a flat-12 laying around your garage... those will fit perfectly into any of the 917s. I do not recommend (per Carl Thompson) to run over 250hp in the 906. It was never designed for lots of HP. The 917(s) ... not problem.
We are planning a big unveiling with several examples at the 2008 Monterey Historics in California. We will have a couple of rollers at that time for sale. I'm confident they will sell fast.
Randy.