Hi All,
This is an old threat but it reminded me of a little pet project I had some time ago. It can be done and you can see an example here:
http://tmautodesk.nettingwork.com/test/nametag.php?text=What_you_need_here
Now, this works regardless of the image color as you can see, what you can do for the specifics, assuming for instance you want to put the first name on the image, is to put this as the image URL on the Marketo email:
http://tmautodesk.nettingwork.com/test/nametag.php?text={{lead.First Name}}
This could work with any parameter you may have, I still have yet to test it with special characters, but that's something of easy fix. It's a rather simple thing to do, but I'm not sure how easy or hard can it be to integrate it within Marketo. In the meantime, if anyone is interested, feel free to reach me.