I found yesterday another page of wallpapers for the iPad.
Wallpapers for iPad
The resolution is correct (1024x1024) and it even offers the possibility to see how it would fix on the iPad display in both positions, vertical and horizontal taking in care even the dock or the top bar.
It doesn't have many wallpapers, but they are cool and since yesterday they have added some more, so not bad at all.
Just another page to get wallpapers for our iPad.