Yup! I went with my arm. (The one I don’t use to write with, of course, heh.)
I’ll be the first to agree that if you want to be able to cover up your donor site, the arm is NOT the site you’d want to go with– in that case, the site you’re thinking of would probably work better. However, using the arm as a donor site gave me the best chances for erotic sensation returning to the phallus once it was constructed, which was more important to me than having a super hard-to-cover-up scar.
It’s all give and take, pros and cons. Best of luck finding the donor site that works best for you! :3