Marion (Rustmanfan) has a lot of blank ones in her 4shared file. You can find the link in the "meet the DISigners" sticky.
I also have lots of "license plate/stroller tags" in my 4shared file in the link in my signature. They are simple to personalize if you have MS Word by inserting a textbox over the image. Here is a link to a thread that will teach you how to use MS Word to personalize blank DISigns that you find: http://www.disboards.com/showthread.php?t=2286193