Using Basslines in A Cappella

Real Ultimate Power from the Bass!

If you were to imagine the simplest arrangement possible for an accompaniment to a soloist, what would you think of? Well, let's say it's one other person -- that's simple. What would they sing? Harmony? Backup vocals? Some combination of all of these? What if you lived in a world such as ours where chords rule the harmonic day? Probably you'd do what my inclination is: Write a bassline (You might have guessed this based on the article's title as well. If so, you are an outside-the-box thinker).