I am collecting ideas for a simple to assemble, relatively inexpensive kit form "Hummingbird" type mini landyacht.

The aim is to design a simple kit form landyacht primarily for children to sail on our most commonly available venues- grass ovals and secondly- carparks.
Alternative types of sails and masts from those already in use are prefered- possibly along the lines of those used in "puddle duck racers" (simple polytarp based sails) and either light steel tube, timber, PVC pipe or some other type of mast- or even a composite mast using all 3?
I have emailed both Fallshaw, and Richmond castors to see what information they can supply regarding thier products- and have an initial reply from Richcastings, but nothing from back from Fallshaw yet.

Remember-The finished kit would need to be:
Easily assembled- no welding by the assembler if possible,
Able to be assembled by unskilled parents and thier children,
As economical as possible, but with as little scrounging as possible- one stop shopping to be encouraged if needed.
Suitable for sailing on grass (light and stable) by an average size kid up to 12 years old/ 40kg or thereabouts.

OK crew, start thinking!

we need dimensions, materials, assembly hints- anything you can think of!

Stephen.