: Do you want a boat that comes apart for storage,

Yap, at least till I can sue off that inflatable beerbag who took over the boatshed in our section of the marina. My attic floor is 10 feet diagonally.
I don't expect instant solutions, but I am sure this thread is worth debating since every now and then somebody raises the storage space subject.
I have indeed a bigger sailboat building project (touring the Mediterranean at the last stage) which is off topic, but some kayaks are as long as some small day or cuddle cruisers, and I assume the structural question is the same on a hard-chined stich and glue or any other boat built with panels , including ply.
And some of us may want to paddle from their own boat!

:or do you want to disable a boat so no one else will use it?

Anybody from my marina (or from this board, though the flight isn't offered) may paddle or sail my real or future boats on a phone call.
Now, even in paradise there are thieves, and by local laws if one of them runs over some swimmer's head I'd be liable to pay the victim a life rent.
The clever feature in a dismantling boat is you only have to take one panel away to make the thing unusable for 11 months.
Kayaks are the most stolen kind of boat (in the US at least) as I've read from a site.

: If you want a boat that folds up, there is a design kicking around for a wide
: "kayak" made from plywood panels that are hinged with canvas.

Romaneck-Rathburn . Built one. Broaches. Yaws. Seems you've paddled one more than once, how realistic is your account.
I've indeed considered adding side panels to her, though the problem here is its width, which is too big as you put it, and difficult to make much thinner. But this deserves a try anyway. You need a very large center canvas hinge to force the spacers in.

: You could also modify the venerable building methods of a birchbark canoe,
: and cover the handmade frame with a sheet of vinyl flooring, (also called
: linoleum by some people) (available in 12 foot widths and LONG lengths at
: home centers) rather than a big piece of birchbark.

Linoleum! Very exciting. Good idea. Worth a try for a skiff at least, or a collapsible baidarka.

As we stand now, I guess that for S&Gs and panelled boats, the best idea would be to use those stringers and those James Bond special joints I've heard about.
Or the bolted way, à la Volkscomponent kayak.

Laissez le bon temps rouler.
Peace