This follows on from the thread here about the feasibility of adapting existing stylesheets to work with Sandbox. Rather than try it with Classic stylesheets, I decided to start with one of my entries to the Six Apart style contest. Two reasons for this: it's more recent which means I like it better, but more importantly it was designed to be compatible with multiple page structures.
Here's the result. I manually linked the stylesheet from header.php to simulate being loaded after the skins. It took about ten minutes to delete the positoning stuff, edit the ID names (#banner to #header, .entry-body to .entry-content, that sort of thing), and the same time tweaking it further (the original template handled dates differently so adjustments needed to be made for that).
So, quick and dirty and definitely in need of more bashing about, but it looks OK in all layouts and once it's been tested more thoroughly I'll be releasing it for general use.