I didn't watch much TV growing up so don't get the TV references. I also think 'Childe Roland to the dark tower came' which is by Robert Browning, Roland from Elidor and The Song of Roland. All very heroic.
I have a 7 year old Roly in the family and he loves his name. He does get called Slowly Roly because he's very laid back.
Also don't let Roly Poly put you off. Overweight children may or may not get teased but their name won't have much bearing on this in my experience.