Mini splits are great but not exactly well suited for RVs. They mostly run on 240V but are not low amperage draw. The 18,000 btu unit in my shop usually draws about 8 amps of 240V... not likely something you are going to do with a few solar cells.
Packaging is also a problem. The condenser unit is not huge but it isn’t small either and the form factor is not well suited to the top of an RV. They like to be vertical and to have some clearance from the wall, like 10 or more inches.
For distributed zone HVAC in a home they are just about unbeatable with efficiency rivaling geothermal and cost a fraction. The inverter technology and zone temperature control are the key. A three phase unit would be even better.
Three phase unit? The one that prompted me to post this to general/chat on FR is a three zone unit, not the same thing I take it. Can you elaborate?