I feel more and more South Indian characters started featuring in North Indian films and advertisements after that phase in Indian cinema that saw Quick Gun Murugan, and to a smaller extent, Om Shanti Om.
Here are a few advertisements, South(Indian)ernized:-
1. The good ol' Center Fresh Ad
2. Voltas AC
3. Mahindra Duro DZ
Is this a trend?
Also, people get very disappointed when I don't talk in a South Indian accent while talking in English or Hindi. I've at times had people requesting me to talk with a South Indian accent.