I posted a comment on your Youtube post, but didn't have enough space to say what I really wanted, so I'll say it here.
I think you handled the situation very well, and I only have a few minor, hopefully constructive, criticisms. You did as well as anyone could be expected to when they are being intimidated by the police. One thing that I find very helpful when dealing with these detainments is to not ask open-ended or simple answer questions. Questions such as, "Is there any law requiring me to...?", leaves them too much room to weasel around and not give any answers in your favor. It is far better to ask the question in order to force a specific answer. "Can you name the statute that requires me to...?" is a more apt question, because it forces them to give a concession. It's even better when you know the specific law being involved, and you are able to quote that statute. If you do know the law, and they are insisting that they know something different, you should politely, but firmly, state the facts and your position. This will help to give you the upper hand in the intimidation game. They rely on tactics to put you in uncomfortable situations and to fill you with doubt. Prolonged detentions and repetitive questions are used to coerce information from you, and to make you doubt what you know or believe about the law.
Escalating the detainment, as you did by asking for a supervisor or by invoking your 5th A. right to silence, will only serve to prolong and confuse the situation. I'm not saying that you shouldn't invoke your 5th, but you should do it only if you intend on not actually speaking any further. If they had made any motions toward you that were consistent with an arrest, such as disarming you, searching your person or putting restraints on you, then that would be the prudent time to use the 5th. You were still in a situation where verbal dialogue was beneficial and had no reason to roll out the 5th. You can, of course, refuse to answer any specific question at any time. Further, asking for a supervisor is a good way to get held down even longer. Had they actually called for one, it could have been as much as an hour before one showed up. They are all getting paid no matter how long the detainment takes. They are not wasting any of their time, only yours. And don't forget that they are all playing for the same team, so there is no reason to expect that a supervisor would have treated you any differently than the officers who stopped you on the street.
You had established fairly early on that they had no RAS to stop you in the first place. About the time that they started in with the "your papers please, we don't know who you are" spiel, you should have politely excused yourself from the conversation, and walked off. You did eventually do just that, and I commend you for it, but it could have happened about 10 minutes earlier if you had not allowed them to bait you into their game. I doubt they would have stopped you at any point during the detainment if you had simply stated that you were ending the contact, and were returning to go about your lawful business. No crime + No RAS = No legal stop. They would have been in big doo-doo if they had tried to physically stop you. Just make sure that you have plenty of room to leave when you do, because even brushing up against an officer's shirt sleeve will allow them to arrest you for battery, as was done to a person in New Hampshire not so long ago.
Overall I think you did great, and the most important thing was that you walked away from it without giving them anything that they wanted. You won, and lived to tell about it. Congrats!
I will be moving to New Hampshire early next year, and I look forward to OCing all over that state, as well as Maine and Vermont. Perhaps we'll run into each other some time if I ever find myself in your neck of the woods.