Sorry for the delay. I love this concept. Definitely needed.
What I wanted to consider is the issue of having to lift the whole thing to switch from horizontal to vertical mode. With some folks here that is a real concern. I think that with a small amount of redesign it could be made to hinge to the vertical position rather than have to be removed and reset.
I have not been able to come up with a solution that is as elegant as your base design yet, but I will ponder it over the weekend.
Excellent concept, great execution, and awesome that you are sharing it!!!