If the Chipettes were around the same original years (1950s and 1960s), I would prefer them over the CGI/Live Action Chipettes. I do prefer the 1958 Chipmunks over the live action/CGI Chipmunks (In English. Korean dub is still better than English, though.).
I would love to see a remake of the CGI/Live Action movies with more realistic-like models and following the 1980s story line. I say the most realistic versions of the Chipmunks are the 1958 versions. Though, I'm not sure if Brittany and her sisters would have their hair up, if they were from the 1950s. This is just a silly fan art, though. XD The Chipettes were created in the 1980s, and Charlene was the prototype for Brittany.
They were diapered in the original sketch, but Alvin was originally supposed to be dressed like Captain Chipmunk. You can view the original sketch here (Along with others that will be worked on). http://sta.sh/01ac7ezh769y
I'm not a babyfur/diaperfur artist, I'm more of a baby rodent/diapered rodent artist. I'm just more likely to draw diapered "furry" art, if it's a rodent. I can do other species, sometimes, even if it's art traded for or commissioned.