Here is something I tried though it is boring so I can't imagine doing it for long unless you are watching tv or something. But I have used this method on occasion. I don't know if I invented it, but I haven't yet heard of anyone else doing this.. Though, I would personally rather dance for cardio (which I do as I also dance and perform dance though I don't do longer shows like you)!
Anyway sometimes when I want something low impact at home I loop a resistance band around the foot of my sofa or coffee table. Then I sit on two furniture sliders and do the same motions as a rowing machine. These are the sliders I use: www.amazon.com/Waxman-4704095N-2-Inch-Reus
These sliders are just like more expensive "gliding disks" called Valslides other than the color and price (and they come in a set of four). There are actually a lot of interesting exercises for core and balance that can incorporate these and some good cardio options. When I travel, I bring a pair of sliders, a resistance band and jump rope for a very small travel gym that fits in my carryon or even a purse. So if you search youtube or google you might see a lot of options using the gliders in case you don't like it as a rowing substitute.