Never seen one. Manufacturers sometimes have one-off models of their boats produced to show to punters, and one of the IPC Editors (Hugo Andreae, I think) confessed to having a model of a Fairey (?Swordsman?) in his office. I have a vague recollection that <A target="_blank" HREF=http://www.airfix.com/frame_set.htm>Airfix</A> used to do them but they don't now - though if you want a scale model of a modern, French built motor boat, they're about to introduce a QM2 kit.
I also note that they still do a Vosper MTB kit; this must have been going for years, because I remember them from my childhood and, believe me, that's a few years ago.
Another possibility is model remote controlled boats, but I've a feeling that, whilst you might be able to get a reproduction of a Cigarette or a Batboat, there is a limited constituency for replica Sealines /forums/images/icons/wink.gif.
<hr width=100% size=1>Je suis Marxiste - tendance Groucho