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.
Heidi Rodney goes by ChocolateGeisha.
Rodney Itier goes by iTz.
Rodney Jerkins goes by Darkchild.
Rodney Cothron goes by Rodimus.
Rodney Browning goes by Nation.
Rodney Waruhiu goes by Rodorious.
Rodney Pike goes by RodZilla.
Fernando Rodney goes by Kimbo.
Rodney Skerrett goes by Mr Uptown.
Red Rodney went by Albino Red.
Rodney Duncan goes by Blade Runner.