I've seen some really good A.I. versions of existing songs that plug in a singer as a sort of "What If?" scenario.
Here's a really terrific version of Alice In Chains "Nutshell" as if it were sung by Scott Weiland in his gritty, Core-Era voice. Or
this one as if Layne Staley were singing "Piece of Pie" from Stone Temple Pilots. And they both sound terrific and quite convincing!