Find your slip first,as by the sounds of it you are looking for housing so the boat is not to important. In that case look at ferrocement. Good insulation properties and you can find them around at very affordable prices.
Here is a 40 footer that would do nicely at an asking of 24.9k
1970 Seasmoke Sloop - Custom Ferro Cement Sail Boat For Sale -
OK you are not going to win any races but you will have a hull that is not going to rot rust or develop osmosis.