1. The OP asked for full-keel boats that go in light wind - with the presumed assumption that ONLY full-keel boats are REAL "blue water" cruisers.
-Simple answer...I assume...is...they don't exist. Full-keel boats are pigs in light air. Can we all agree on this?
I don't agree. I'll grant you that there are some true, full-keel, light air pigs, but not all of them. Sailing in light air has a little to do with the boat and alot to do with knowing how
to sail in light air. If you don't know how to keep a full keel boat moving in light air, you probably won't do much better with any other boat, because, the fundamental principles of sailing are exactly the same, whether you're on a full-keeler or a fin-keeler, and, if you can't keep one driving, you probably won't do very well with the other.
Almost anyone can sail a boat reasonably well in 10-12 kts of wind, because there is enough wind that you can afford to waste
some of it and still sail reasonably well. The reason why light air sailing is so difficult is because you have barely enough moving air to move the boat, and you can't afford to waste any of it. Therefore, you have to not only maximize the amount of drive that you extract from the moving air with the sails, but you also have to minimize the amount of drag wherever you find it. Most people don't do either very well in light air.
I frequently crew on a friend's old Alberg designed full keeler, and we consider light air our chance to beat some of the modern fin keel racers, not just on handicap, but scratch. We don't beat them all, because there are always a few guys who really know how to sail in light air, but it's amazing how many modern racers drop out and start their engines just because they can't keep them moving.
You don't often hear a boat owner say "I have no skill at light air sailing." They usually say "My boat is a pig in light air."
Logic tells us that you ought to be able to spend lots of money and get a boat that performs better, but that only works for power boats. In sailing, it doesn't work that way. You still have to know how to make it go.