Depends on the quality of site you want. If you want something that really stands out you probably want to order something from designgururyan.com or minisitegraphics.com. Other sites to check out are listed below. Remember, you get what you pay for.

http://www.minisitestudio.com
http://www.pulpminisites.com
http://www.graphicsgenie.com
http://www.minisite911.com
http://www.lucyweber.com
http://www.graphicsunloaded.com
http://www.minisite-wizard.com
http://www.minisitespot.com
http://www.sbographicsdesign.com
http://www.edesignwiz.com

Some of site packages come with banners, if they don’t or you want to get your own banners made I highly recommend bannersmall.com