I want to discuss the greatness that is Rosa Parks and more specifically the ending of the song when there are multiple layers going on.

All at the same time you've got;
-the hook
-Dre saying "lackalackalackalacka backalackalackalacka"
-Big Boi saying "get back, get back, get back"
-Dre and vocalists singing "ahh haa, baaaby, baaaby, ahh haa" (might not be exact but you know)
-scratching

the track is beautifully layered and mixed. joints on the radio nowadays are as stripped down and simplistic as possible, and Rosa Parks was the exact opposite.

Big Boi kills it. Dre absolutely destroys it.

The breakdown section with the harmonica is dope as well…but the layered vocals at the end is what gets me every time.

Are there any other examples of this in Hip-Hop?

on a side note: I remember recording back in the day and explaining to my boy how we never did anything to that effect and we kept it too safe etc etc and his response was "if I got in the booth and was like "backalackalackalacka" you would tell me to stop the dumb shit and would erase it" and he was exactly right.

That was and is the beauty of Outkast. They pushed the envelope and executed every time. They knew that Andre saying that dumb shit was dope as hell and made it all work.