you could try a bit of Radiohead. Some of their stuff is very easy to do acoustic. Although, the guitar can be quite hard. Counting Crows are mostly acoustic, you could try Mr Jones. Although, I've never seen the tabs for that so I couldn't say how hard it would be. Incubus have done some very mellow stuff. Wish You Were Here and Drive being pretty outstanding. Ofcourse, Clapton is always a classic. you'll never be able to play it, but you want to listen to Classical Gas just to realise how good tihs man really was.
If I was on my other computer I'd be able to give you a bit more help. I might add to this at some point.
Jim.