I would like to invite discussion about a "junket boat" - the bare minimum.
A knockabout rowing/sailing dinghy which does not want an outboard, and which is:
* cheap and easy to build
or, may be available second hand, for JR conversion
* for those who are unable or for whom it is inconvenient at the time to travel to a junket under sail.
Ideally it would be transportable on a car top (just) or with a very light trailer, and able to accommodate an air mattress/sleeping bag/canopy arrangement (just).
These two almost contradictory criteria intersect at about 12' (or, say, 4m).
Too large for a tender.
The concept is to simply gather a small local fleet of same design hulls with any sort of junk rig, provide fun, compare rigs, create opportunity for bystanders, and serve as a place to camp for the night at a summer junket.
Here is an example:

This is a Welsford Golden Bay which Marcus built many years ago, taught his kids to sail, did a bit of camping.... Its 12'9" (almost 4M).
He hasn't got it now, but he bought another one recently and put a junk rig on it and car-topped it to the "Tall Ships".
Here it is:

Apart from the actual race, it did more actual sailing at the event than all the other junks put together.
I've now bought one too. Here it is:

Its flat bottom is fine on a light, general-purpose trailer. Just needs converting, as soon as I can get a round tuit.
Here's another one for sale locally:

There is a very good chance this is also going to come into the JRA and get a junk rig put on it. If so: job done. A potential local "little fleet" of junket boats, hopefully with each with different types of junk rig to mess about with. No need for a new design (although that would be great) and no need even for a new build.
Although, that would be great too, of course.
David T has suggested the Selway Fisher Drake 13, there might be a few of them around for sale in the UK - and/or someone willing to build. Interestingly similar - yet different. Perhaps a little fleet of these might appeal to some boatless junkies in a local area in the UK - again, cheap, easy to build, easy to transport (flat bottom, don't need a proper boat trailer), capable of camping in (just.)

David D suggested the Wayfarer - great idea. A bit big perhaps, but there must be plenty of them around in the UK, on trailers - the Wayfarer would make as good a test platform for comparing dinghy junk rigs as almost any small boat you could think of. You should follow that up, David.
David W. put up a lovely design of his own, which would convert nicely.
And there is no shortage of beautiful but simple little flat bottom American designs which would tick the boxes admirably.
So, there's the idea.
This is my inspiration - Freebie - though unfortunately he is too big to be easily transportable and needs a trailer. (Try clicking on this image).
Anyone in the NI NZ up for getting or building a Welsford Golden Bay and making it into a junket boat?
The real challenge comes after the gathering of a suitable junket boat "little fleet".
The real challenge lies in designing the rig. Any dinghy rig must be capable of being assembled in a jiffy (say, 2 minutes max) and dismantled just as quickly. This is a tall order for the junk rig, which is far more suited to being left in place for instant deployment on a moored boat. But not impossible, I believe.
I can't offer a prize, but I hope this thread, and the committee tender competition, will both lead to a new development - the practical dinghy junk rig.
Or, should I say: the practical junk rigged dinghy.