Vidqun - Any idea were we can get a copy of the TDOT on line, I can't find one? I think you'll find that most scholars agree that the city in Isa 19:18, is Heliopolis, as the oldest xisting text of Isa read city of the sun. The change to destruction is presumed to be a typical hebrew play on the word "Sun" and "Destruction".
I do not agree with you that there is no historic fulfilment of either Isa 17 and 19. Damacus was taken by Tiglath-Pileser III between 738 and 732BCE, and Egypt was invaded by Esarhaddon, all these events are recorded on ABC 1 (BM 92502), as well of the sacking of Babylon by Elam in 694, which makes Isa 20 refer to this even and not the later defeat by Cyrus.
Viviane - Are we restricting the use of a post written prophetic/ History or did you rule that out in the OP?