high density screens/retina displays support
Fist of all, thank you for your awesome library!
Then, nowadays, high density screens (or "retina" displays) are spreading out really fast and unfortunately jqPlot doesn't support them which makes every generated canvas look blurry.
If you look at this pull request from flot, it doesn't seem like supporting high density screens is really complicated (at least for someone who truly understand how your code works).
So please, consider adding such a scaling fix to jqPlot core.