are there any unicycles that have disc brakes or a kit for doing that?
I think this might be more of what your looking for.
Disc brakes are a bad idea on a unicycle. they would be hit and dented every 5 seconds by rocks ect. On a coker they might work though.
they use disck brakes on high end mtn bikes
but high end mountain bike don’t take the abuse a muni does. when a mountian bike falls, it usually pretty much stays were it is. when a muni falls, it goes richocheing(sp?) down rocks ect.
also, there isn’t really a point to get them, because normal brakes work plenty well.
why did you make two exact same threads at different times? 
and high end mtb’s are going WAAY faster than any unicyclist I know so they need that much more stoping power
becuase someone told me to