Try wrote:
I have been trying to find out how many hump=backed A-4Es there were?
So far with no results. Any one have an idea. If you check the books
about the A-4 there is a complete absence of info about how many A-4Es
were fitted with the Avionics hump. Being and old AK, at one time, I
would have thought that such information would have been in the A-4E
IPB. Does anyone know? Walt

Try researching at http://www.history.navy.mil/avh-1910/APP09.PDF.
Looks like some work but you may find your answer.