NW3: Wasn't really intending it to be a retrofit - just something that could be incorporated in to future aircraft.
But can you imagine the reliability/certification/maintenance issues involved with this? The Mark I eyeball, when used properly, would seem to be the best device for this job.
However:-
2) Abolishing the no smoking sign (or at least have it painted on or something) and replace it with a mobile phone sign (some companies allow you to use them on the ground until the doors are closed etc.), and possibly an electronic devices sign (who knows in the future!)
Agreed. This would definitely be a good idea.
3) For the crew, how about making all the meal service stuff disposable (inc cups, glasses, trays), then you could just tip everything in to one of the big boxes, and not have to worry about putting things on shelves etc. You could then have a thing to compress it all down back in the galley and take up loads less space - this should mean a much faster serice and easier for the crew.
Have you flown from London to Paris or Amsterdam? This is already done - and has been for a long time - on routes like that.