Funny how once it gets rough, the cameras stay in the drybags!
Anyway, you don't need to look any further than this site to find a rough weather handling video - except that the main RIB.net site seems to be down at the moment.
Go to rib.net and if I remember correctly, there's a "publications" link. Then look at "video" and the "RIB Cruising" video. The rough water bit might not be exactly what you're looking for - I'm thinking of the section on the way back from the Scillies - there's a subtle difference between a good helmsman who makes it all look very easy, and the narrator when he takes the controls and the nose of the boat points skywards most of the time. Also a good moment when the driver of the Gemini takes his eye off the waves and goes very nicely airborne. I love the sound of an optimax out of the water!
More of a winter warmer than a teaching aid. Maybe I'll take the video camera out and try to do a suitable video. Now all I need is a helmsman (or woman) with some good heavy weather handling experience. Mrs Jackeen??