(NASHVILLE SKYLINE is a column by CMT/CMT.com Editorial Director Chet Flippo.)

The recent use of the so-called Tupac Hologram to seemingly bring him back to life has stirred up much discussion. Seeing the late artist "performing" again onstage at the Coachella festival in California has caused much speculation on the increasing practice of bringing back dead superstars to record duets or to perform again. There has been talk that the resurrected Tupac Shakur might even go on tour again, through the wonders of new technology.

The Tupac illusion, however, was not a true hologram. It was a 2-D illusion, a holographic projection, rather than a true free-floating hologram. The much-talked-about upcoming London appearance onstage by Queen's late lead singer Freddie Mercury in the long-running musical We Will Rock You will use what Queen guitarist Brian May calls an "optical illusion." So there still isn't a true 3-D musical hologram.

You could always do what the group Journey did in replacing a departed (but very much alive and well) lead singer with a sound-alike. At least it appears that the band haven't attempted to have any plastic work done on replacement singer Arnel Pineda to make him resemble Steve Perry.

Or you could emulate the great Keith Richards, whom many have accused of being one of the walking dead for years. It appears he will outlive everyone.

The Elvis in Concert tour has been packing in huge crowds, especially in Europe. Mainly because Elvis never performed outside the United States (except for five Canadian dates in 1957). Why? His manager Tom Parker was an illegal alien and was afraid of leaving the U.S. and perhaps not being readmitted to this country. The current "concert" consists of stage footage of Elvis performing, with all the backing musicians and singers stripped from the footage. Instead, Elvis on-screen is now accompanied in the theater by an orchestra and by such Presley band members as James Burton and Ronnie Tutt. It is said to be a very tasteful and fitting musical tribute.

But is it necessary? Where do the profits go? Does Elvis ever rest well? Did he sign a living will, insofar as to the disposition of his video likenesses and performances and use of his vocals?

The large Elvis song catalog has lent itself to many half-dead, half-living duets. He did an entire Christmas album with living country artists such as Carrie Underwood and Martina McBride. Elvis' sturdy bones have turned him into the dependable pack mule of the dead. Besides a number of country Christmas duets and other projects, Elvis was joined by his daughter Lisa Marie for "In the Ghetto" and "Don't Cry Daddy."

Country music has been fond of putting current artists together with now-dead singers but mostly only in audio recordings. Of course, these days ,you generally get a better class of music from the dead than from the living.

The 1989 video duet of Hank Williams Sr. with Hank Jr. on "There's a Tear in My Beer" was a landmark for the genre. Unfortunately for Hank fans, he left very little else in the way of performance footage. The Hank Jr. thing was, of course, patched together long after Hank's death. He performed a duet with Anita Carter in 1952 on "I Can't Help It (If I'm Still in Love With You)" on Kate Smith's TV show, and that video clip is still available.

One bizarre country extreme was a duet with two dead country stars singing together: Patsy Cline doing "I Fall to Pieces" with Jim Reeves, for a 1982 tribute album honoring both artists who had been killed years before in plane crashes.

The late Reeves also did three duets with the living Deborah Allen. And Cline's voice was patched into the album Duets, pairing her with such artists as Willie Nelson, John Berry, Mila Mason and Bob Carlisle. She also recorded several video duets on the TV show Ozark Jubilee, but the clips are not readily available. Her duet partners included Red Foley, Ferlin Husky and Cowboy Copas. The late Keith Whitley recorded "Till a Tear Becomes a Rose/Lady's Choice" with his widow Lorrie Morgan. And the late Roger Miller recorded "Old Toy Trains" with his son Dean. The older Miller had written the song as a Christmas gift for the then-infant Dean.

The dead Tupac recorded in an unlikely pairing with the Notorious B.I.G.

The late John Lennon rejoined the Beatles briefly for "Free as a Bird/Christmas Time (Is Here Again)," as well as for the single "Real Love." Nat King Cole recorded a duet with his daughter Natalie on the song "Unforgettable." Death didn't keep the late Jim Morrison from recording an album of poems and spoken word snippets with his group the Doors.

The dead Frank Sinatra sang with Tony Bennett, Luther Vandross, Carly Simon, Celine, Barbra Streisand and a host of other pop singers. And there have been many other such examples.

There has also been some dark speculation about actually cloning a superstar or two, through use of their DNA. I suspect that the music industry would stop at nothing to get the big money-makers back on the road.

Thinking about this subject reminded me of a short story, "The Monkey's Paw," by W.W. Jacobs. Published in 1902, "The Monkey's Paw" has had a fairly long life.

Not to give the story away, the plot is a simple one. An elderly couple and their son come into possession of a monkey's paw, which will grant them three wishes. What those wishes are, and how they come to be granted, make this a deadly effective horror story. Just imagine the agony of a dead soul slowly and painfully burrowing up out of the coffin and then beginning the agonizing crawl for miles to get to ... ? The theme of the story, not surprisingly, is about bringing the dead back to life. And about the unknown consequences of that.

The story has been anthologized dozens of times, made into plays and movies and parodied on The Simpsons. It also was an inspiration for Stephen King's Pet Sematary.

Elvis and Hank, and all the other late artists, now pretty much fit the classic definition of the zombie: a dead person brought sufficiently back to life to be a passive slave worker for its master.

In zombie state, dead artists are the perfect workers. They demand nothing, they have no expenses, they expect no payment and they deliver exactly the same performance onstage every night. And, importantly, they cause no trouble for their masters. Elvis can't shoot the TVs in his hotel rooms anymore. Hank doesn't OD anymore.

Personally, I think it's creepy and unseemly to try to haul dead people out on the road or to "record" duets with the living, to line the pockets of who knows who. Call it a tribute all you want. I still think it's exploitation of the dead -- who, after all, have no defenders. Let them rest. I have always felt Elvis had a pretty bad time of it in his unhappy life. Allow him to rest quietly in peace there in the serenity of the Meditation Garden at Graceland.