We recently built a double storey house with a monument roof colour and the rendered wall colour which looked fantastic was Taubmans 'Abstract'. With fencing in Colorbond fencing colour 'woodland grey', balustrading in a powder coated black colour and garage door in powder coated silver colour with black accents. I think colorbond steel colours which look good with Monument would be Shale Grey, Basalt or Wallaby depending how warm/cool you wanted to go with the colour scheme.