First off I feel like I owe Vetter and Dulce Suema an apology. I am sorry for snapping at you both.
I did want to address Omaho's comments:
In terms of the comparason of the Tartan 27 to the CD 27, I would like to hear the basis for saying that the Cape Dory will outsail the Tartan 72. I have not seen any reason to believe that to be even remotely true. Besides for the Tartan 27 typically rating 21 -27 seconds a mile faster than the Cape Dory 27, the Tartan will outpoint the Cape Dory by quite a bit. In terms of ease of sailing, the Cape Dory 27 is comparatively tender and develops a wicked weather helm in a stiff breeze. While the Tarten will develop a bit of weather helm as well, you can 'trim' that out with the centerboard resulting in a nicely balanced boat that still points well and makes minimal leeway. Even in terms of motion comfort, the Tartan has one of the nicest motions in a chop of any 27 footer of that era that I can think of. I have always been impressed by it. The Cape Dory not so much, tending to be a real roller and pitcher.
While the Cape Dory 27 does have a much nicer looking interior, and certainly a better offshore layout than the Tartan 27, it is not as livable an interior if the goal (like the OP) is a summer liveaboard. In terms of build quality, S&S was one of the first design firms to begin to understand the need for internal structure, smaller panel size, limiting flexure, resin ratios, and upping the ante on material handling methods. And Tartan had evolved from a company that built one-design race boats. The construction methods and engineering on the Tartan 27 were quite sophisticated for that era and the typical hardware and deck layout was first class for the time. By any objective standard, in comparason the Cape Dories were pretty crudely built.
Lastly, I don't know why you personally are not a fan of keel centerboard boats but I would suggest that this is a great way to go for a small cruising boat offering shoal draft, and as compared to most liong keel boats, typically offering much better performance all around.
I would look at a simlar boat, Cape Dory 27 or 28.
The CD 27 will outsail the T 27. There may be a higher price on a CD 27.
They do retain value if maintained. I'm not a fan of Keel/center board boats.
The construction of CD is better over all. One is for sale up in Winterport.