TM,
13 These are the names of the sons of Ishmael, listed in the order of their birth: Nebaioth the firstborn of Ishmael, Kedar, Adbeel, Mibsam, 14 Mishma, Dumah, Massa, 15 Hadad, Tema, Jetur, Naphish and Kedemah. 16 These were the sons of Ishmael, and these are the names of the twelve tribal rulers according to their settlements and camps. 17 Altogether, Ishmael lived a hundred and thirty-seven years. He breathed his last and died, and he was gathered to his people. 18 His descendants settled in the area from Havilah to Shur, near the border of Egypt, as you go toward Asshur. And they lived in hostility toward [c] all their brothers. GEN 25:13-18
I find the key words NEAR THE BORDER OF EGYPT and HOSTILITY TOWARD ALL THEIR BROTHERS to be key pointers themselves. Who else lives near the border of egypt other than Arabs?
This link might be helpful to your inquiries.
http://nabataea.net/12tribes.html.