Danny,
Welcome to the forum. I interpret Dave's comment above as he is saying it is really tough and not something he might do in any time soon, if at all. I could be wrong.
He is currently close to finishing up the Sierra Sat that is hopefully releasing soon and then it sounded like his next project might be a Sierra tower or bookshelf with a diamond tweeter. He has said it will be at least $6000 for a bookshelf implementation though because of the high cost of the diamond tweeter.