Can't speak for the others but we had no idea what anyone else was doing. I was looking for a boat to do Marathon with, had always liked the Sunseeker Tomahawk and thought that it would make a great Historic boat. After some investigation it was apparent that the hull wouldn't take the race punishment (in other peoples opinion), and I would have way more invested in the finished product than the boat would be worth so that idea was scrapped.
Peter Martins from Berserk very kindly offered to design me a boat, and as it turned out we already had a hull design we had been testing on model form that we were very impressed with, so to cut a long story very short we used that and Petter and I worked together on the top half. Kitten and our customer had developed the hull shape from the customers original drawings which we then scaled up from 30' to the UIM length of 34' plus the extension on the back, to make a larger boat we would need to be a bit creative with the local real estate!
How much? Well like the others we haven't finished our first one yet, and ours has a windscreen and roof (the roof is optional). Also we don't have a rubrail as the boat is seamless (all will become obvious when you see the next lot of photos on the build thread). Race boat layout with no cabin floor (the leisure version will have a small cuddy with a V berth double and mini galley with heads under the berth), engine lid etc will probably start somewhere around the £35k + vat mark, but that would go up a bit when you start adding the shiny bits! I reserve the right to put that up when I work out how much this one has cost me!