I think the whole concept of cemeteries is grim and sad, and not a celebration of the person and their life.

I'd much rather see a flat, toughened screen above each grave, set into which is a touchscreen, like in museums and art galleries. An interactive presentation about the life of the deceased, their favorite music, family photos, genealogy, etc. are all available.

As we live our lives, we have the choice to record key moments on disc (like a time capsule) and leave these to be played via the lifemask after we are gone. Then families and friends visiting us can hear us speak again, which would be very comforting. The touch panel activates the list of disks and allows selection.

There is also an option to record a message so that other visitors can know you were there, or just because it eases you to perhaps say something you always meant to, and didn't.

This would also be great if you have any items of family history that are very notable. So many stories die with the old people, and you never really know how it was to live back when they were young.

The genealogy option would allow researchers to tap into an IP addressable unit to harvest that data. Eventually there would be a worldwide web of the dead.

Power could be provided from solar collection. Graves are usually in pretty sunny spots.