I think Hellosailor is 100% Correct. I cruised and lived aboard a Hunter/Cherubini 37C for a year with my ex-wife and then 2 year old daughter. (Our divorce had nothing to do with that year). The issue once you move onboard is how much stuff you cannot bring with you. It's very easy for many people to miss that point. That is why people are suggesting bigger offshore boats.
I am currently renovating a 41' Seawolf which I intend to live aboard and cruise. I chose this boat because it was built for long-term Ocean Cruising. As a result, there is a plenty of logical storage space for living aboard and enough headroom for me. (I am six feet eight).