I've choreographed a few low-level dance numbers for shows, either for myself and my partner, or for my students. Typically, I'll combine a couple of compulsory dance patterns, adapting the rhythm as necessary. For example, I'm going to do one for a very beginning adult couple for our holiday show. The music they want to use is in 4, so we'll do the Dutch Waltz in 4 as part of it. I'll make up my own steps for the introduction, finish, and transitions between patterns. I'll usually try to break up the pattern, so the skaters aren't just doing laps of the rink, which looks pretty boring to the audience. For instance, I might do an intro, a lap or half lap of a dance pattern, some kind of diagonal, another pattern, and a finish. If the skaters are up to it, I'll throw in some free skating moves like spirals or lunges. So the number will be based on dance patterns, but not actually be just a demonstration of the pattern.
The last number I did for my partner and myself combined steps from the Swing, Fiesta, and Rhythm Blues, plus some original footwork, a pair spiral, and a simple dance spin. At the end I did a lunge that changed from forward to back. In other words, it was a very simple free dance.
His club does adult group dance numbers for their shows, very much like Skittl described. My club doesn't have enough dancers for a group number yet.