If I were visiting Belgium horns would not usually be at the top of the list well at least not until now. After I had my fill of fine Belgium Ales and food horns would be a great idea. The Horn Academy builds very high quality horns. It appears the site is run by Philip Mundi who builds the horns designed by Mr.Iwata as well as some fine reproductions. It is refreshing to see some curves published for these horns. If you have JBL, Altec, TAD, or other high quality drivers these guys can help you out.
Check out these horns. The wood version of an Altec 1505 is stunning. The pics on the site aren't that great but at least the horns are. There Klipschorn LF build is stunning. The built in corners definitely help performance.
“I like big horns and I cannot lie, those little horns make me cry” Tom Danley "Simple. A horn is just a reasonably rigid boundary for an air column. Now all you have to do is figure what shape to make it." PWK