I am going to vote against the idea in its current incarnation, though I think the concept itself has some potential.
I don't think it's a good idea for the TalkBoard to be involved in the actual thicket of designating Ambassadors and monitoring their performance.
I like the idea of the TalkBoard creating such a program, though I think it needs more work before actual launch. But I don't think we're well positioned to run it day to day. And I don't think we're likely to have sufficient knowledge of posters across all relevant forums to make a decent judgment, either.
I also don't like this being bestowed 'politically' from outside of a forum. Rather, I think that each forum really ought to be honoring its own. We'd have to think through how this would work, but I'd really like to see this ultimately be a kind of 'bottom-up' honor for the knowledgeable, helpful, welcoming posters in each forum.
And I also don't want to exclude anyone from participating, either. It's hard to imagine not asking that lucky9876coins act in this capacity in the UA forum...