Do you have any photos? It sounds magnificent. I like all the colorbond photos http://www.houzz.com.au/photos/exterior-photos/colorbond-

I was in favour of a colour similar to Jarrah but my daughter disagreed. My concern with black is that the decking is a shade of blue/grey and the house has much grey as well. I really like the black(ish) look but the pics shared show it on quite light surfaces i.e. cement or a very light wood colour. I actually have a full tin of blackbean wood stain. Do you know this colour?

I'd be worried that red brick , presumably white door jambs , then a walnut or mahogony ( dark walnut ) look door will look cliched 70's . A cedar or even something like Jarrah will be different enough to the brick ( again , making the assumption you have crisp white or similar to break the tones ) to look the part IMO . Of course , the actual design of the door will have a slight bearing , but personally I can't think of too many options where I would prefer a walnut or mahogony tone , unless you were really embracing the era and have yellow dimpled glass inserts too haha .

I think its too dark , too grey , and that the darker tones don't show off the Merbau timber well ( or vice versa ) . Personally , I think either go lighter on the walls ( surfmist or similar ) , keep the monument roof , then a bright colour on the trim and entrance and garage doors -- red , orange or yellow are my favourites , but on your design it may make something nice look a bit too 'slapped together transportable building' , and in fact almost any colour may suffer that fate , so how about a rock look for the base , rather than timber ( whether you are going light or dark or natural , it could look like its just waiting for someone to knock off those base timbers and back a truck under it ) . The other combo that may work would be your darker colours , but have varnished light beech or similar for the base , decks , even the entrance door and garage door ? Basically , someone going to the trouble of varnishing looks more permanent than anything that looks like it is or could have been stained IMO .