I have heard that the Shadal used a razor to remove his beard, justifying it for himself through the Ibn Ezra's interpretation of Vayikra 19:27 that the prohibition would only be for shaving the beard for the dead. Is this true, and if so, how would this be allowed if there are no authorities that permit this?
ואני גם כי אינני מאוהביו כבר קיבלתי פירושו (נגד ההלכה) בפסוק לא תקיפו פאת ראשכם שאינו אלא על מת וקִבלתיו לעצמי למעשה אע"פ שאין אני מורה כן לאחרים כי אין לי עסק בהוראה
As for me, though I am not one of [Ibn Ezra's] friends, I have already accepted his explanation (against the halacha) in the verse [Leviticus 19:27] "Ye shall not round the corners of your heads", that it is only over the dead. And I have accepted it for myself in practice even though I do not rule as such for others since I have no business in ruling.
Here is an image of the relevant portion of the letter: