For the chairs, I purchased the This old house set of drawings for starters - I've sat on those chairs before and they are very comfortable, plus they don't have the vertical support piece you see on cheap-o chairs. I plan to modify to suit my taste, make templates, and reproduce enough to sell to friends/neighbors/local flea market etc.
edit to comment to top post on this page: the heat from that fire will flow above those bricks for the most part, so cracking shouldn't be a problem. Even if stacked to a 2nd row, I wouldn't worry about that. It would have to be a HUGE fire.. but since his design is so simple, you could always replace a single brick very easily if needed.