Thanks for your tips everyone, I'm very thankful
The Wish List goes like this.
Weather constraints: mild winters, hot hot hot summers
Predator constraints: foxes, hawks, snakes
Pest constraints: wild birds, mice, rats, possums
Deep eaves for shade
Raised roosting and nesting boxes to provide cool shade beneath
Roosting box enclosed on 3 sides
Fully enclosed attached run
Dutch door to run
Run divided into "rooms" so weeds can grow, new pullets can integrate, sick birds can be put in "hospital"
Paved apron
Run roof: half solid, half mesh
Removable roosting bars
Easy clean roosting box: I'm thinking of a dropped floor with sides 30cm deep, with an external side open-down-and-out on hinges so litter can be swept out into the wheelbarrow and then into the compost
Access to roosting bars for midnight capturing
External access nesting boxes
Rainwater capture and storage
Breezeway for hot summer nights
Big enough for 9-12 chooks to live harmoniously: 20-30m2
I think that's everything... Now I better start saving up