Barry Sanders
Yes, He was a running back as well as a defensive back for Florida State. Nicknamed " Sunshine Scooter"
Ryan Grant
Since 2009, Rashard Mendenhall is the number one running back on the Steelers.
Kordell Stewart, nicknamed 'Slash', was able to play quarterback, wide receiver and running back during his career.
Elroy "Crazylegs" Hirsch (June 17, 1923 - January 28, 2004) was an American football running back and receiver for the Los Angeles Rams and Chicago Rockets, nicknamed for his unusual running style.
Ernie Davis, the first African-American to win the Heisman Trophy, was nicknamed the Elmira Express by a local sports columnist.
BenJarvus Green Ellis "Law Firm" is a running back for the NE Patriots.
Current Arizona Cardinals running back Edgerrin James.
Mike Hart who is the current running back coach for Eastern Michigan University played college football as a running back for the University of Michigan.
Dulymus Jenod McAllister used to play for an NFL team as a running back. Nicknamed 'Duece,' he participated in college football while attending Ole Miss.
The nickname given to him was "Law Firm." I do not know the story behind the nickname though. Hope this helps! ;)