I didn't read all 4 pages of this thread. My advice would be to not risk it. You may be legal but, the police officer may not know the exact letter of the law. I keep all open containers in a closed compartment outside of the passenger compartment just to be on the safe side.
For example, my pickup truck has a tool box mounted in the box of the truck. I always put any alcohol in that and close the lid. I've never had a problem with a police officer opening and looking in the closed tool box.
Of course, I never drive with any alcohol on my breath. I practice my own personal "Not A Drop" rule. Don't give them a reason to be suspicious and then they won't be.
Oh, and, If you didn't know, a open box of beer is considered a open bottle in many states. Even if your not drinking and there is no actual open can of beer. I have heard things are different in Texas and just wanted to let you know this.