Visual designer Louie Mantia, has created a truly impressive collection of themed wallpapers for iPhone and iPad. His bold Lego brick line-up includes blue, green, red, yellow, dark grey and grey after downloading. I liked the Lego pattern more as a lock screen than as a home screen.
You can find over 60 designs tooled by Mantia including unique expanded desktop versions, with one that's definitely worth a look by Super Mario Bros. fans. Did I mention that these are all free?