Out of curiosity, what drives the "plenty of cargo space" requirement? We're a family with three kids and bought a 6-seat Mazda 5 this year as our only car, on the theory that it has almost no trunk space, but mostly we're just bombing around town doing grocery runs anyway.

In cases of cargo moving (dump dropoff, IKEA pickup, Home Depot), it's typically adult-only trips, so it's really just vacation that's the case where we need a full load of both passengers and cargo. Since vacation is only a few times a year, we figured we'd optimize for the common case and plan to rent a larger van for those instances if necessary, or look at other alternatives, such as a roof box, trailer, whatever.

For my fiancée and me, we need cargo space for two primary use cases: 1. short-distance hauling of large objects and/or numerous objects, and 2. road trips. It's the frequency of both that encourages the purchase of a large vehicle rather than the rental of one.