I've been surfing for author caricatures to hang on the walls of my classroom. One way to enlarge clipart is by making a copy on a transparency. I then project the image on a piece of butcher paper. You can make the image as large or small as you like. Once you have the size you want, trace the image onto the butcher paper. These caricatures are 2 feet tall. Laminate your project for durability.
I'm hoping these "characters" will speak to my class about the importance and fun of reading.