Those are nice, and minimalist simple. I was originally pondering how I might build a rack, and thinking about something adjustable, came up with a design requiring 6 pieces - a base, a column, a cross piece and 3 horizontal supports (2 adjustable).
Now after seeing this, I'm wondering what I would have to charge to render this design in one solid piece of wood. With it's inherent weight and some non-slip feet, it would be resistant to moving.
Steve