Is there a CSS sprite generator that also gives retina -versions?

[mrmcq]

If there already isn't one, I would very much appreciate if someone could give some instructions on how to make a retina and non-retina CSS-sprite myself. Preferably using some CSS sprite -generator in the process if possible.Related to topic: http://miekd.com/articles/using-css-sprites-to-optimize-your-website-for-retina-displays/Thank you all in advance!