Today I discovered Southern Girl Blog Designs. Although she does not appear to offer any free blog backgrounds, her portfolio suggests that whatever she charges is well worth it. In addition to doing complete blog schemes for Blogger blogs, she also does headers for WordPress & TypePad. She also designs Etsy banners and avatars. My favorite parts of her site (as one who cannot afford a professional blog makeover at this time): Her monthly giveaways to Followers and her tutorial sections. Here is a link to her instructions on creating a 3rd column in a Mininma template:
http://southerngirlblogdesigns.blogspot.com/2009/04/creating-3-columns-in-blogger-minima.html