Ok, if no one has, I will do it! I will dehydrate them then blend them into a fine powder and use them to colour a small batch. I'll report back in case anyone else wants to know.
I bought carrots this weekend and thought about your post actually. Was going to try it but ended up drying cilantro instead for a citrus cilantro soap I was doing - I would love to see how the carrot tops work out though!