You have opened a can of worms haven''t you? Although I will probably get blasted for this, of the big three, Hunter, Beneteau and Catalina, to me, after looking at used boats from the big three, and years of racing on and against Catalinas, Catalinas clearly seem to be the lightest duty of the big three in terms of build quality and the 270 would not be a boat that I would probably ever consider for the kinds of plans that you have outlined for yourself. Of the big three I think that Beneteau seems to do the best job of producing boats that I would consider taking offshore and even then there are things that I would want to do to make sure they were more suitable.
Of the big three, in the general size range that you are considering, one boat that has really impressed me for what you want to do has been the Beneteau 31.7. I had the chance to study these boats while I was Italy and was very impressed with how they stood up to the hard usage of a charter fleet in the sometimes very windy conditions of the Mediterranean. I would think that you should be able to buy one of these used but in good shape for way less than a new 270 and really have something worth while.