iPad-Wallpapers - The Best iPad Wallpapers on the Internet. iPad-Wallpapers.com - The Best iPad Wallpapers on the Internet. - Home
I don't think I've seen the site list here so far, but the folks from SciPhone who brought us such a great selection of iPhone wallpapers now has a site for iPad wallpapers (link above.) They seem to have the most wallpapers collected so far from what I've seen.