I stumbled on the MAP stuff later last night after more searching. A place called Sweetwater has some pretty good prices.

It was extremely hard to find any really cool enclosures though. Most manufacturers are either in Taiwan/China or Europe (Velleman).

I also found a cool diagram on a DIY speaker page: http://www.t-linespeakers.org/oddsends/box/ This shows a very nice and simple box made using wide U-channel extruded aluminum. This is what I'd like to do for a custom project (see the projects forum). Now I just have to know where to source that design of extruded alum.

Bruno