I think what you're asking about is referred to as "character modeling"

Different people's voices sound unique because of physical variables in their moth, nose, tongue, vocal chords etc. TC Helicon has a few products that allow you to remodel the variables to sound like others. They have a hardware and software product that offers some capability in this arena.


http://www.tc-helicon.com/products/voicepro/
http://www.tc-helicon.com/products/voicemodeler/

There are also two versions of the voiceworks ... the more expensive version (plus) adds vocal modelling to the pitch correction and harmonies offered by the basic version.

http://www.tc-helicon.com/products/voiceworksplus/

Apart from these products, I've never seen any other product that claims to make a singer's voice sound like someone else.

FWIW, they used to call it "voice modelling" but people complained the results were too cartoonish... which may explain the new term "character modelling"

https://www.dropbox.com/sh/ey71h8ep047758h/AAC12jNM0Hz9Q8zsh5iDeqNHa?dl=0