Just donate any amount (even a penny), and it will send you to chosen wallaper. Here are the sizes, but if you want more options, let me know and I can probably make ‘em. :)

1024×600
1024×768
1280×800
1280×1024
1366×768
1440×900
1600×900
1680×1050
1920×1080
1920×1200