You can use carrot baby food, but why not use pumpkin? I have made and will be making pumpkin soap today using pumpkin for color. I like the idea of saying it is pumpkin soap with real pumpkin!
You can either add a bit at trace (which I have not done) or substitute the pumpkin for some or all of your liquid and mix the lye with it. I did it that way, and it was pretty. Since I use GM, I actually dissolved the lye in pumpkin as half of my liquid and then add the GM (or other liquid) after it was dissolved. Very pretty color.
Good luck!