Well you can find them online. It's hard to find them in stores. I have looked everywhere. Just find them on ebay and see if they are available in the sticker section.
I would totally try Ebay. I haven't personally bought a dog sign before, but I have had other custom signs made by Ebay vendors. Good quality and can be personalized.
Typically the best place to find cute, funny, or kitschy items for dog-lovers is on the internet. If you search around, I bet you'll find the perfect sign! There is a lot out there to choose from.
