A 380

[MaximumPete]

The A380 boasts a full compliment of ash trays, as well a a set of permanently illuminated "no smoking" signs.

It's FAA regulations to have ash trays, but I'm not sure about their regulations about smoking on aircraft.

Perhaps it's time for them to update their regulations.

MP;)

[Fargoo]

Plenty of people still either deliberately or just absend mindedly light up on board if the signs weren't there people would just assume they were allowed to smoke.
Ashtrays are still on the outside of toilets because a lot of people still try and have a sneaky smoke and need somewhere to stub out when they get caught.

[320DRIVER]

For the Airbus SA aircraft I think they offer the option for the 'No Smoking' lights for 'PED (Personal Electronic Device) OFF' light. If that's the case, I'm sure the option is available for the Big Bus so it is the client who has to pick his choice from the catalogue.