Flying with lots of photo gear [closed]

I have a flight from Europe to US (with connection in Zurich) next week and need to take a lot of photo gear with me: three cameras (DSLR, SLR and a medium format), a number of lenses for them, a light meter, some film and a laptop with charger. I plan packing it all into my small carry-on roller bag. My checked luggage will have all my other stuff like clothing etc.

The airline (Swiss) allows only one cabin baggage and it's weight limit is 8 kilos. My cameras and lenses alone weight a little more than 7 kilograms, add to that the weight of the roller bag itself and it is roughly the max allowed weight. But then I still have to put my laptop, film and other stuff like jacket, passport etc. somewhere. For that purpose I'm thinking to also take a small backpack with me.

How likely am I to encounter issues if I say that both my backpack with a laptop and an 8 kilogram roller bag are cabin baggage? What if my backpack contains not only a laptop, but is also full of photo gear? Are there any specific rules or practices that allow for more/heavier photo or video equipment taken as carry-on? As I won't dare checking my $$$ worth of cameras and lenses with other luggage, what are my options if I'm refused to take both bags into the cabin and allowed only one? What is more likely to slip, two bags or one, but heavier than 8 kilos?

Basically, how do photographers fly with lots of heavy photo gear, especially those with big medium format (6x7, 6x9) or even large format cameras?