Firstly, the word Allah in the Bible is never used as a Reference to God, so its not wise to start thinking so Jesus could have done so now or whoever you think was on the cross.
oh, and im sure Jesus was "merely a prophet", thats why history revolves around the dating system of BC and AC (yes im aware that is was changed in 2002) ... Was Jesus merely a prophet that the worlds historical dating system was changed according to his Life?
Arabic and Aramaic are semitic languages as far as i know, they may be similar, but not the same. Saying they are similar is not good enough, its unlogical, i hope you agree.
Eli, Eli - Elah, Elah, Allah, Allah
For people to claim Jesus said Allah Allah on the cross, would be quite a laughable claim actually.
El is the hebrew word for God like i pointed out, and by adding the possessive suffix of i, it means "My God" ... Jesus did not say Allah on the cross.