Here’s a selection of orange and brown wallpapers that work well with the Ubuntu coloured themes such as Dust, Human etc.
Coffee Cup (My Current Wallpaper!)
Normal resolutions: 1024×768 1152×864 1280×1024 1600×1200
Wide resolutions: 1280×800 1440×900 1680×1050 1920×1200
Spider And The Web
Wide resolutions only: 1280×800 1440×900 1680×1050 1920×1200
Vector Art
Normal resolutions only: 1024×768 1152×864 1280×1024 1600×1200
World Map 3D
Wide resolutions only: 1280×800 1440×900 1680×1050 1920×1200
Forage Bows
Normal resolutions: 1024×768 1152×864 1280×1024 1600×1200
Vista Sun
Normal resolutions: 1024×768