If you've ever been to deviantArt, then I'm sure you've been pressured or even thought about signing up for a subscription. Well, they have something called deviantMobile where you can send a good majority of the deviations to your phone as a cropped wallpaper. So there's another HUGE source of wallpapers for pretty much any resolution phone, so long as you like the crop.
http://mobile.deviantart.com/verification/ <-- free test to make sure it actually works for your phone.