Jerry, here's an idea:

tunr the thing on its head. Decide first on the 2-3 (or 5-6) aspects of songwriting that you want to promote in the workshop, and then find (others') songs that exemplify those points. Even better, invite the participants to offer suggestions for other good examples from their experience.

Such "aspects" could be (but are not limited to):
- saying a lot with few words (the opening of DR is a good example)
- melody enhancing the lyric
- using "hooks" in lyric and/or tune
- structure of story line (serial, back to front, flashback, static)
- rhyme enhancing the story (especially internal rhyming)
- unusual subject
- unusual viewpoint
- 1st person versus 3rd person
- etc etc