Irb was designed as an electronic version of "Pocket Changes". It has evolved to include a wonderful player feature. With the added real estate available on the iPad, I'm confident evolution will continue.

I can imagine a separate stand- alone app for lyrics-sharing as well as another app for melodies.

These could be multi-tasked to display concurrently, still in separate line-by-line horizontal tiles, on the screen of individual devices by the end user for their personal use.