The original can be found here.
I brought this to BronyCon with the intent of collecting as many related signatures as I could. What I got was that (barring Meghan McCarthy’s, thanks to a combination of shenanigans on Saturday and the fire on Sunday), plus Tara Strong gushing over it, plus Lauren Faust telling me she was impressed with the detail. ^_^ And that’s not even the most exciting thing that happened to me there.
For minimal completion I’d probably have to grab Ashleigh Ball’s and Tabitha St. Germain’s signatures at some point, but what I’ve got on there at the moment is: Tara Strong, Lauren Faust, Andrea Libman, Cathy Weseluck and Amy Keating Rogers.
EDIT: Snagged Rebecca Shoichet’s and Tabitha St. Germain’s signatures at BronyCAN 2013.