I think it's a possibility that Mat is Artur Hawkwing, and don't see why everyone is so very against that. I just read a posting that suggested that Mat's memories come from the threads he pulled along the Pattern as ta'veren in a past life. Since a lot of these memories focus around Artur, and he was the biggest ta'veren of the time, I think it's plausible that he is Hawkwing. Yes, there is that whole thing about AH showing up when Mat blew the horn, but that could easily be countered by saying that time flows differently in t'a'r, etc. etc. Neither side has enough proof to definitively say which is right. I think it would be cool if Mat was indeed AH, because then I think Verin would be his daughter (there is a passage that describes how Verin says "It's time to roll the dice, as my father used to say", or some such thing), and that whole thing would be pretty weird. Of course, I'm just speculating, and I'm probably wrong.