Great Bear: Do you mean that only Tawils who are Cohanim go back to Eli? There must be some Tawils who are not Cohanim considering that Jews were probably taller and healthier than Arabs and many were called Tawil which then became a surname.
I never heard of a Tawil that isn’t a Cohen so I can assume that they all got their name from some tall ancestor.
I also believe that all Maslaton’s like the one from Ahi Ezer are Cohanim.