If you are using MacVim I suggest you set your background transparent and you will be able to see the cheat sheet while editing. Set it something between 10-20 percent and you should be fine. For example:
This wallpaper should 'work' with both the dark and the light theme of solarized. OmniGraffle files are included if you feel like customizing this to your own vim colorscheme.
Thanks to @EspadaV8 there's a dark version of this wallpaper now as well.
There is also a version with a 'real' background based on tremblingpixels' breathe wallpaper now:
We also have a version that preserves the gradient of the original, but changes the color to a nice soothing blue: