There's already been one movie on the subject, THE MIRACLE OF OUR LADY OF FATIMA, released in 1952. It was not an A picture but it holds up surprisingly well.
I believe I've heard of that movie (and might have taped it on EWTN recently). I rented "The Song of Bernadette" last summer and my 6 y.o. (then 5) LOVED it.
I'll have to see if that is the movie I have on my DVR, and if not, I'll add that to the Netflix list. :)
Thanks for the info, either way!