Im doing much the same thing, see my thread
here.
Have you seen the cabin Pacific
here?
It's a lot of money but it's a lot of boat, may be ideal for your needs.
There's also a project Arctic 28
here
but be careful, a new set of tubes for these to the same military spec will set you back around £7000
Arctic 28's are as standard kitted out for 2 crew and 8 passengers.