So, to experiment we just used a pole between two chairs. But later a friend of mine and I modified two saw horses as a stand, with a 4x4 turned kitty corner mounted between them. We then sanded down the edge to round it and varnished the wood to smooth it. It took only a few hours of actual work and a day to dry. This went in his barn. You'll want a ceiling rope to stabilize so your sub doesn't fall off. Or hands to hold.
Haha, I was thinking of trying a pole between chairs. Your final setup is definitely much more impressive than what I could make though.