If you want it to recede into the surroundings use a dark colour such as Woodland or Monument. Use it on walls and roof. Using it vertically and horizontally would add a nice feature to it when up closer. The hardwood for trims, architraves, etc. would look fantastic, in particular if they were kept oiled rather than left to go grey.... A light colour would mean the dwelling could be cooler in summer perhaps but shading from tree's may work just as well. If a light colour was used it would stand out from kilometres away.... not ideal at all.

apennameandthata i don't know... vertical is more shed like style, while we still have a colonial style base and veranda. Dust will be an issue here (although its not so bad in that particular spot on a river, good protection from trees) but pressure wash will be regular practice anyway. Thanks for all your suggestions and I will take all on board, especially sandstone ideas. I don't this I want this house to look pretentious, but how can I describe that, I am after some subtle "wow" factor or something a bit different, but it must look like we knew what we are doing and YES, I want it to look like high quality build and not a transportable house or kit home. The house rectangle is so simple that I worry it may have that boring factor in its looks and that is why I am looking for some ideas. My problem is a tendency to overthink but I hope I will find a balance at some point :) At this stage I think: galvanised tin everywhere (or that zincalum), rusty steel posts, aluminum windows with timber look, sandstone features around main door and sandstone chimney. We had a big flood last year and the spot never goes under water, its on high grounds even though it is only meters from the river.

Look at 'Iron Ash'. Its a treated version of what you're after. Don't know anything about it but seen it recently on the web. Overall avoid Merbau as mentioned above, as well as being an imported 'sustainably' managed timber.... Use local product's when available as they're manufacturered to high standard's, supporting local job's, companies must meet tight regulation's, etc. unlike other countries....

It certainly could be real wood battens bigreader, as it looks like a true timber product - I'm just hoping that it's not and that it's a product/panel that can be easily purchased and used to achieve the look.