There's a new Salthouse "picnic boat, about 30 or 31 feet, by the same design team that did the South Star. Don't know whether it would go on a trailer, but it's a stunning looker. If you want a classic take, look up Peter Sewell's "Whio" - bit of a "Q Ship" as it looks like a classic double ended launch, but planes. Made the cover of Wooden Boat magazine a few years back, and warranted a significant article in the mag as well. Goes like a robber's dog with (from memory) a Toyota diesel out of a van. And it's trailerable (just).