There have been a few articles recently about Google\'s new imageless buttons:
The biggest problem you are going to have will be making it work across browsers.
I think you should strongly consider whether you really need it ... Google gets a lot of bang for the buck by making something like this because of the vast number of buttons and languages that they need; I suspect that most sites and applications would be just as well-off using an image.
An open-source component is a good idea, though: spread the wealth and effort widely.