It would be great if Queen Silvia wore the Cameo tiara at the 2015 Nobel Prizes. It would also be exactly 10 years since she wore it at the last Nobel event. If she does not wear it then, I would love is she wore for the King's 70th birthday in 2016. I would guess she will wear the Braganza tiara, but she did wear the Connaught tiara at his 50th birthday, maybe she plans on wearing different tiaras for the King's major birthdays. I also don't think there was a tiara event for his 40th birthday.
It would indeed be nice to see the Cameo tiara again on the Queen, on any event. I'm a bit torn about her wearing it on the King's 70th Birthday (if any gala). It would be nice to see it and it would also be a nice gesture as it is the Royal couple's 40th wedding anniversary the very same year. At the same time I'm hoping for the Braganza tiara. On the other hand are be probably seeing three incoming state visits from three Kings in the year to come, so if she continues her tradition it is the Braganza tiara she will wear for these occasions.