If you do an Amazon search for “String Quartet Tribute” you’ll find lots of selections. I’ve listened to samples of some of them. I’m torn in buying some of them, particularly the U2 and Foo Fighter tributes. However I’m very much aware that there is a good chance that some tracks are indeed elevator music. “Closer” by Nine Inch Nails is just plain awful in string quartet version. The songs that sound good are the ones that are ballads. “All I Want Is You” by U2 comes to mind. “Yellow” by Coldplay is another good one. I find myself wondering what “Under the Bridge” by The Red Hot Chili Peppers sound like.
It may all be just a fad, kinda like the bluegrass versions (Pickin’ on…). Many of these albums just came out this year or last year. I’m not sure who is this 4 person string quartet is. But it looks like they just go around covering other people’s songs somewhat as a novelty album. And then make money off of die hard fans that need it for their wedding.