Limeberry is a CSS 3 Finely Granular Color Gradient Generator. It allows you to input very precise (up to the nth decimal) numeric values to be used as your gradient color stops. Choose how many color stops you want and then define what colors you want at those stops.
This is definitely early beta. It's functional, but only just (but hey, I did it in an hour over my lunch break).
Check out the project page to see the roadmap and for info on how to contribute (this is an open source project).
This was developed with Chrome, but early testers have informed me it works with Firefox and Opera as well (yay!).