This would be a good question for the guy that created taibo. Can we all take a moment to laugh at combination workout/self-defense videos? Martial arts are already work-outs, you don't need to combine them with dance moves to get in shape.

Oops, better get back on topic. Hmmm....thinking off the top of my head, what does any martial arts need?
1. Students
2. Fighting Techniques (whether practical or not)
3. A Master
I suppose with those 3 elements, anyone is qualified to create their own martial art. Even our friends over in the workout video industry could say they've created a martial art combining aikido with ballet. Will the students be about to defend themselves? Who knows, but that doesn't mean someone can't come along and create that "martial art" anyways. All he/she would need is students and fighting techniques, then buy a black belt and refer to him/herself as "the Master".
By the way, be on the look out for my martial art I'm creating that combines Muay Thai, Yoga, Scuba Diving, Interpretive Dance, Cricket, Hapkido, Break Dancing, Sheep Wrangling, Sky Diving, and Astral Travel into one extreme, end-all-be-all martial art. Just need a name now.....