Well, there are a couple of things I can think of off the top of my head, but may not work for you. One, I can set you up so you can post and nobody other than moderators can view what you post. Works great for your build thread issue, but anything you post in other threads would also not be viewed by the members.
Otherwise you could start the thread in the
supporting members lounge and only the other supporting members would be able to see it, which is a small percentage of the members on this site. I would think the members there would honor your request for no posting. In the future if you decided you wanted it visible to all I could move the entire thread into the project updates forum.