I have a Noelex 30 which fits all the parameters you are looking for. Boat is for sale in Australia.To see what these boats are like search for Noelex 30 in Boatpoint website. These are a Bruce Farr designed 30 foot keelboat with a hydraulically retractable bulb keel. The boat is trailed on a tri axle trailer behind a Toyota Landcruiser at 3500kg for boat and trailer. The mast can be raised with an A frame and trailer winch singlehanded, it is easier to do singlehanded unless your assistant knows exactly what procedure is. With the keel and rudder locked down the boat will pass category 1 stability requirements. several years ago a Noelex 30 was a regular starter and finisher in the Sydney to Hobart yacht race.
I have just returned from several weeks cruising in Bass Strait and the Tasmanian coast with my three sons. Some of the passages were in 35 knot plus winds which the boat can comfortably handle. I have the boat set up as a "race" boat with all gear and systems functional and strong. However, it is a light displacement boat and feels much more comfortable in a safe anchorage with all the cruising boats when it is 50 knots outside.
I believe that the 30 foot trailable/retractable keel boat is the ideal boat for a family with kids where the boat is essentially a floating caravan. Pack a windsurfer on board so that you can sail to your hearts content when it is windy and leave the boat comfortably at anchor untill your kids get to the age that they make you take the boat offshore in 30 plus knots (or take you along for the ride).