Creative Commons symbols made it into Unicode, and all of these availabe in Symbola and Unifont already. While it's tempting place these in the footer, but thinking back these are really not any better than a plain CC-BY-SA at the moment due to font issues (unlike the author, I am not going down the web-font path). Perhaps we can do ghetto versions of these like how we used (c) for the longest time? Maybe after all the badges we saw on websites, stuffing the same things into Unicode is the next boom.