A word about boat choice: yes there is lots of space (i.e. volume) in a modern wide-sterned shallow-bilged production boat, e.g. Beneteau/Bavaria/Jeanneau/.
There may also be a lot of cabins.
This is all good, but big open
cabin spaces aren't all that useful, after a point.
We recently bought our future liveaboard yacht, and ended up going with something older which packed in a lot more stowage (i.e. lockers) than the more modern boats.
We looked at some newer boats and found that the
headroom and feeling of spaciousness was great, but when you opened up lockers often they were very shallow or already occupied by the
water tanks,
calorifier, fridge
compressor, etc. The remaining locker space didn't seem adequate to us for liveaboard use.
Perhaps the more modern boats are designed with the
charter market in mind, where people will have only a small amount of luggage to stow.
And yes I know it's all a bit of a generalisation, and I do think modern production boats have a lot of great qualities, but just wanted to make the point that 'space' is about more than just overall
hull volume- it's how it is apportioned as well.