Suppliers -- initial thoughts

OK so we don't know who we're going to building with... or if we'll be building it all ourselves. I'm hoping we don't shoot ourselves in the foot as we can only get one OB licence every x number of years.

But some thoughts as to materials and suppliers:

Timbercrete-- fireproof, termite proof, single skin means no need to line inside
Concrete Slab Floor -- termite proof, easier to clean, we can colour it at minimum cost. It is a garage but we have painted and lino'd our garage floors in the past as DH likes working on cars!
Mono String Stairs -- e.g. Like these ones by Iron Bark Black Smithing
Velux Skylights (or something like the Skywindows by Skydome) for upstairs -- Maybe in replacement of the dormer windows! I like the idea of looking out to the sky from inside! Could be hot so maybe only on the southern side?
Floorboards laid on particle board upstairs
Aluminium Windows downstairs for low maintenance (I prefer the look of wooden windows but maintenance and bush fires will make aluminium a better choice)
Colorbond roof -- lined on the inside