There are some excellent liveaboard articles all over the Internet
which detail people's answers to the questions you are asking. You
could start at http://www.irbs.com/directory/Dmoz/Living_Aboard/ .
And of course you could check out the liveaboard section of the finest
boating site on the 'Net at http://www.casualsailor.com/LAIntro.shtml
..

I really do believe that there is a "minimum" size of boat that people
can tolerate. For Florrie and me, it was a 38' motor yacht. However,
a broker we know lived with his wife on a 25' sailboat for a while.

I'd agree with the respondent who warned that most people can't deal
with it. Florrie and I love living aboard, really love it. But it's
clear that most of our friends think us extremely eccentric.

Hope this helps. Good luck!

E.J. Bleendreeble
http://www.casualsailor.com