It seems like this is a question that has not been succesfully answered and now I have clients that want to see it happen.  I know DJI sells the power cables and start/stop cables for the Arri Alexa Mini but before I waste my money DOES IT ACTUALLY WORK??

From my understanding: Not without modifications. The main problem is the p.o.g. which is far too much to the rear when putting a mini in the mx. You might work with conterweights or you extend the arms. Meaning cutting them apart and putting an extender piece in. There is a Ronin mx user group on Facebook, they discuss this issue. In my eyes the Ronin mx does carry a ARRI ALEXA MINI exactly like the S1000 carries a RED. Only in the advertisement of DJI ;-)