If your site supports PHP you could generate the images on the fly. PHP GD libary supports *.png transparency overlayed onto another image/backgroud colour.
You can overlay any True Type font. Each time the page loads you could make the server generate them, or perhaps if the colour only changes every so often make it save the images to the host server and reuse them.
You couldn’t really mix it too well with CSS, but it’s an idea.
