It has been done! In particular a look at the "quack" that Coulton used in his version (instead of cussing like Mix-a-lot did): http://geeklikemetoo.blogspot.com/2013/01/about-that-quack.h...

He also points to a great example indicating that the beginning was likely edited too: http://imgur.com/a/F0HTP#1

Also, if you're someone that trusts their own ears and has headphones, you can hear Glee's in your left earbud, and Coulton's in your right, in this pairing: https://soundcloud.com/suudo/joco-vs-glee-baby-got-back