RE: A real STARTBOARD LONGBOARD???
The SUP seems to have little to do with windsurfing. It's just a large surf / paddle board that you can attach a sail to as well. If I didn't know better, I might think I am in a time warp - 1970's.
Starboard seems to have fun coming up with unusual boards that appeal to a very small percent of the market. I don't fault them for this, it's just surprising.
I don't think they are trying to come up with something for the masses, just experimenting and having fun with varying concepts.
I still race my original 1985 superlight a couple of times a year, plus I retired my last race long board - Equipe II XR a few year ago. Given my 23 year experience with long boards, it's difficult for me to conceive of a long board that will have universal appeal. It's a good concept, I just don't know what could be. You certainly can come up with a good recreational board or a good race board, but a combination of the two will be difficult.
However, if one design racing is the goal, a good recreational board could be raced. Performance would be limited, but in one design, it doesn't matter too much. On the other hand, except for Olympic class racing, I don't think that one design racing will never again be big. Too few people interested in racing and too many other windsurfing options.