The several definitions of ballad have been given in another thread sometime in the past year (and probably several times before that). OED 1.-The original sense of a song to accompany a dance has pretty well been lost.
OED 2.- A light, simple song of any kind; now specifically a sentimental or romantic composition---
OED 3.- A popular song, spec. one scurrilously attacking persons---
OED 4.- A proverbial saying---.

OED 5.- A simple spirited poem, ---originally sense 3, in which some popular story is graphically narrated---.
This is the sense desired by McGrath, but unfortunately one that only a few people would hew to. I think that Bev, who started this thread, is seeking examples that fit this sub-category.

OED 6.- Use in words or comb. such as ballad-monger, ballad farce, etc.