There may be holographic tombstones in the movie Serenity, but who knows how long they might have played after Mal and River left the scene? When the 'verse is that big, they probably don't come back to visit that often and don't worry about it.
However on this planet it is another story, and if you come back to visit your beloved, the video better be running. That's why Vidstone developed the solar powered Serenity Panel, 'Utilizing ground-breaking solar-powered technology, this weather-proof LCD panel provides families and friends with a timeless way to commemorate a life that’s passed at one’s final resting place." We think it so appropriate that they named it after the movie that inspired it, too.
It adds about two grand to the price of a conventional tombstone and has a waterproof 7" screen. Four hours of sunlight will play a ten minute video six times. Michael at Groovy Green notes that
'There’s even a head-phone jack to limit your groove from beyond the grave to inquiring ears only."
Michael also notes that while it may be solar, it isn't very green. "But seriously, do the world a favor and forget about investing in this junk. In fact, put your money somewhere else — a charity, a family member’s trust fund for college, a random person in need. Buy yourself a plot in a green cemetery and leave your body to become a part of something bigger. Those actions will go a long way to cementing your legacy than some $2,000 LCD panel."