I used to subscribe to a magazine called Multihull International in the 80s & 90s. It was truly international and covered events and new designs from all over the world, although mainly the UK and Europe.
I have just found the Dec 93 copy. It covers events like the Australian 5th National Trailable Multihull Regatta, preview of the 94 London Boat Show, A "Design Concept" - A 6m Planing Catamaran ! and a review of a "Harbour Island 30" Trimaran designed by Douglas A Zurn from Ohio, USA.
It was published by Chandler Publications Ltd. in Totnes, Devon UK.
I have just done a google search and it looks like it is still in print. http://www.multihull-international.co.uk
It does seem to concentrate on the larger cats.
It has a different publisher, but still in Devon.