I saw this one. No mention of copywrite or trademarks tho... so not sure there, http://www.etchworld.com/media/ecom/prodlg/c-animals-0002.jpg
Also one thing I have found, when you do a google image search, if you click on "advanced search" you can select an option thats called "Line Drawings" I have found a wealth of artwork that way in a pinch. Also try www.clker.com.