Attached Link: http://www.elite-expressions.com/homepage.html

John Gryphon's "Elite Expressions" site has 12 different "Environment" sets. Each is a giant cylinder texture mapped with a 360 horizon & sky, with a matching textured ground plane. Super items I use a lot! They're in his free stuff along with a ton of other thing's he's made. He's had bandwidth problems, so if you download much, please consider making a donation to help support the site via PayPal. (It's not required.) Failing that, check out some of the beautiful renders in his galleries & post a comment in his site forum.