A cube van will give you more room in the back, but it'll drain your wallet when it's about fuel. Also you might be pulled over pretty often since some cube van drivers are hauling heavier freight that they were supposed to...
I've been in this business for over two decades now and yes, I can say it can support a family. It takes some sacrifices (being away from your family for long periods of time), but again, it can support a family.