Just to keep this on topic, there's a great interview with Nigel Irens about the two AC boats here . Highly recommended reading.

Martin,

Sorry, I'm not the person you are looking for. I don't live in Brazil anymore and never sailed an F18.
Your man is Eduardo Penido in Rio. Last time I checked he was having plugs made for an A Class and an F18.
He won an Olympic gold medal in the 470 in 1980 and campaigned for the last Tornado olympics. He also represents North Sails in Rio and is the current chairman of the Rio de Janeiro Sailing Federation.
His company's website is http://www.edupenido.com.br/maxiboats.html - you will find reference to his F18 there.

Robi,

I've been once to Quito, capital of Ecuador, but never to Guayaquil, were people can sail. Quito is in the middle of the country, no sailing is possible.
Checking the website of their ISAF MNA (http://www.sailecuador.org/) I found no reference to multihulls of any kind, only 7 affiliated clubs and 7 affiliated classes.
I have a close Ecuatorian non-sailing colleague, so in case you want to ask about other things just send a PM.

All the best,