We just bought a new bike and I had to make a box for it. It uses one sheet of 9mm plywood and a few printed clips.
I had the seat further back (hence the unused slots), but then the handlebar would decapitate the children while steering (though that might not be the case with a cruiser handlebar that I want to install).
Next up: A canopy.
Cool!
Very nice. Is it hard to balance with one child in the front or do you always have two?
I usually have one, rarely two. You get used to it. 
How’s that do on hills?
Should be fine, battery drains faster. Where I live everything is flat. 
This is really great, I love that textured ply, does it have a name?
In one of my projects I used cable ties instead of a plastic pin. I think I perhaps got the idea somewhere on this forum. Not as easy to disassemble but it’s also very neat and strong.
In German it’s called Siebdruck. I’ve got no idea about the English name though, sorry.
Is that the same as Siebdruckplatten? Literally a plate of Siebdruck?
Yeah, kind of. Though I still don’t know how it is called in English. 
Google translate says “Siebdruck” translated to “screen print” / “screen printing”
There’s a brand called buffalo board, it’s also called tuff board, non slip ply or phenolic coated. The thinner stuff, under the brand hexa plywood, is what flightcases are made of.
I found it eventually by describing what I meant in a builders supply and the sales guy said ‘oh, you mean trailer board?’
Grippy on one side, smooth on the other, I think it’s cool too.
In the UK it seems to be called phenolic plywood. Can’t find a reasonably priced supplier near me in Edinburgh 
So cool. Also I notice the V1 logo!
You even covered it!!! Nice!
are you planning for a canopy for the driver too?
No.
There is a product you can get through signmakers called MDO. It stands for Medium Density Overlay. Think resin impregnated plywood with an overlay of MDF material on the sides and completely waterproof. I have used it for a few thigs including gantries on some of my old CNC machines.
Rain jacket and waterproof pants, perhaps.
