My wallpaper is a pic I took during a school trip. I took a bunch of my kids to Howe Caverns in NY, and managed to find the room where the Ommegang Brewery does the cave aging for some of their beers. Very simple picture - cave walls and roof, and case after case of yummy beer stacked floor to ceiling.
I know this is an old thread, but just came across it and wanted to contribute in case anyone else finds it. Here is a collection of high res brewing wallpapers: http://www.brewitagain.com/pages/wallpaper. Enjoy!