Shakes: Top Note Down & 3-Hole
In your lessons I teach that a shake should always start with the bottom note (and commonly with a dip if it's a bendable note). This is the case... most of the time.
Top Note Down Shake
Listen to the last chorus of Big Walter Horton's famous blues harmonica instrumental "Easy," and you'll hear on bar 6 that the 6+ is played as a 6+/5+ shake (this is due to the dissonant sound of the 6+/7+ shake option... the shake focused downwards still gives the melody the variation he was looking for, but with less dissonance).
3-Hole Shake
Most shakes are over two holes, but James Cotton uses a 3-hole shake that sure sounds nice when the moment arises for a more over-the-top sound. Check out Cotton's "The Creeper" from the Best of the Verve Years release, at 2:06.