Rod.
Since this is my name, you'd think I had the answer of a more common short name or nickname for Rodney but that's why I'm here, after all. I was curious if there was another nickname, maybe used more widely in other countries or something.
I doubt this counts but my friends often just substitute famous people for a nickname and call me: Rodney Dangerfield, Rodney King, Rod Stewart, etc.
Patrick Rodney Barnes goes by Rodney.
Fernando Rodney goes by Kimbo.
Heidi Rodney goes by ChocolateGeisha.
Rodney Pike goes by RodZilla.
Rodney Waruhiu goes by Rodorious.
Rodney Jerkins goes by Darkchild.
Rodney Itier goes by iTz.
Rodney Cothron goes by Rodimus.
Rodney Browning goes by Nation.
Red Rodney went by Albino Red.
Rodney Skerrett goes by Mr Uptown.
Rodney Dangerfield went by Jack, and Jackie.