George,
Speed is good for a number of reasons, not to mention the pleasur eof good performance, and you don't need to consider slow boats for strength or carrying capacity. And I would not use careening-cabability as a decision factor, relative to the tradeoffs you would accept, it aint worth a thought.
I happen to know if an good example of offshore ability and experience, which doesn't need to be slow, overweight or ugly, a proven cruiser with two successful South America trips, that has been refitted to go again. She even has about 10 inches of freeboard for dumping another thousand pounds of stuff on board, and will still float on her lines.
See:
http://www.usedboats.com/used-boat-655232.htm
Good luck.