I'm shopping for a used Prius as well. I've found that they made a Plug-in version from 2012-15 which has better options and runs cheaper than the base models. I don't know if satisfies your cargo needs, or if they are only available in some states, but worth checking out. Apparently they leased them very, very cheap, so there are a lot coming back on lease returns that should be in very good shape.
Here's another question - what do you do if you don't have a trusted mechanic? We just moved, and don't take our car in for repairs much at all anyway.