A simple way to adjust or tweak a theme to your liking can be as simple as a few lines of css code in styles.css. I made a couple very minor changes to achieve the affect of a new background color, content on the right when it was always on the left, and a font color change to go along with the background better.
I'd really like to see some more BlogEngine.NET themes take advantage of the new WidgetZone and cool features of version 1.4. To that end, I wanted to see how difficult it would be to do this myself. As a .NET architect and developer I haven't found myself doing a lot of css and UI interface work recently, but figured if I can do BizTalk, SharePoint, EntLib, SQL, WinForms and even ASP.NET development, HTML and css might be possible. Besides, I'm only adding on to what other artists and geniuses have already done.