Taylor was easy. Hornung was perhaps not the greatest runner but was such an impressive all-around performer, so he gets a vote. After that is was tough. Hinkle was worthy. Green was worthy. The rest had outstanding periods of time but they were all pretty short-lived periods.
I also thought about Johnny Blood (McNally), the Vagabond Halfback and charter member of the Pro Football HOF, as worthy of being on the list. Certainly things were different then in terms of the halfback position and what it entailed, but he was quite a runner by all accounts.