It is exactly that, a vector of Rainbow Dash. Once again my wonderful naming skills show up.
I'd define her as... "Pokerface". Taken from the very first chapter from Friendship is magic. Thought it was fun.
If you follow me, you guessed already that this is the vector I based This wallpaper from: [link]
As I said, I NEVER give vectors a lot of time. Mostly other kinds of deviations. You'll want to kill me when I tell you I had started this vector on early December. And Well, it took about four hours over all that time. Counting that a lot of times I just opened the .SVG file and stared at the screen unwilling to do anything else.
Enough description. If you are still reading this...
See you guys.