Songs about making or at least referring to art:
"Your Song", Elton J. (cf. "Song for Dead Blondes").
"Watercolors", Janis Ian (shudder)
"For Free", Joni Mitchell
"Vissi d'Arte", Puccini
La Boheme, Meistersingers, and isn't there an opera about Tasso?
"Brush Up Your Shakespeare" (Porter)

Akiba, you are right, this is not easy, especially for folk songs. Is this because of the stance of pseudo-spontaneity? I can only think of the Bard of Armagh. Did anyone ever set MacNeice's "Fanfare for the Makers" to music?
What a trash bin....

Yours, Peter