The event: Gamestorm 2012, Portland Oregon, Saturday March 24, 2012
The scenario was based on the early 60's SF classic book by H. Beam Piper: "Lord Kalvan of Otherwhen". The story revolves around a Pennsylvania Statetrooper who gets carried crosstime into a world that is very similar to the 30YW. In this battle we fielded fairly balanced forces. Very slight rules modifications were made to correspond to the book.
My writeup on my blog is here: http://viking-wargamer.blogspot.com/ I've reported on the convention in general & about the blackpowder game at the end. A few pictures are included.
My impressions: Blackpowder Pike & Shotte gives a very good, easy to teach game with a very period flavor. Artillery does little as you would expect. Cavalry is a hammer, but Infantry is the deal closer. I highly recommend the rules to any gamer. Be sure to preorder the rules - they're worth it!