There certainly is a boat that meets your requirements, the Cape Bay Fast 40 I've seen it on a trailer. It is very light and only 8' wide. The name is Lawndart and I think it's the most appropriately named boat I've ever seen. From what I've read it weighs 4,000 lbs.
Transpac 03 Boat Bios
FAST 40 - Sailing Anarchy Forums