That's awesome! My friend and long-ago business partner was a unicyclist, and did mountain unicycling for a while as well.
He recently switched to going around with free skates - I'm trying to learn them as well (I never did get around to picking up unicycling unfortunately).
Think a rollerblade turned sideways, so that when you are standing neutrally you are moving in-line with your shoulders (like a skateboard), and the wheels from each skate form a single straight line.
When I read this description, I assumed the skate was attached to the feet like a rollerblade, but after looking at YouTube, it’s more like each foot gets a little foot-sized skateboard. https://www.youtube.com/watch?v=AuR-uxPTGzI
He recently switched to going around with free skates - I'm trying to learn them as well (I never did get around to picking up unicycling unfortunately).