BUT, as I am ever in a debate mode here are some historical precedents and some of my own thoughts having been looking hard at the region lately.

Here is a JSTOR article from 1973. Dated yes, but the folks in this region don't follow timelines the way westerners do.
http://www.jstor.org/pss/2569059

The seed for the Pushtoonistan concept was planted in the 1947 at the time of the Partition of Pakistan and India. The Brits offered the NWFP residents the choice of Pakistan or India, and not of joining Afghanistan. It is deeper than that as it actually goes back several dynasties of Afghans claiming Peshawar, but for sake of this argument the 1947 date will suffice. There was a movement in the tribal agencies for a plebiscite for self determination as had been held in Kashmir. Pakistan held on and defeated this movement despite a 1949 Loya Jirga in Afghanistan in support of Pushtooinstan.

In any event there exists a deep rooted concept of pushtun ethnic unity that could be the basis of a greater organization.

Now looking at it many of the points made by council members are valid, an overt "state" would be futile. We cannot think in the terms of state in this region. That the Pakistan Taliban and the Afghan Taliban are one in the same, which is the concept here. Traditionalist Pashtuns forming up across the border as a tribal confederacy of sorts. The Taliban may be seeing greater gains in driving into Pakistan as it only has to face the Pakistan Army vice NATO. But this concept of Pushtunistan goes beyond that. It allows them to operate cross border without thought.

In any event the prominence of the minorities in the Afghan government are also a driving factor. Pashtuns are the majority but may feel under represented in the government. The Pashtuns Traditionalist may be looking at the world in a different way, a state for the Pashtuns, ethnically and religiously “pure”.

By the way I am not advocating this idea, I am only looking at the fight we have and see a change in the goals of the Taliban and their supporters. Namely the formation (even covert) of a Pushtoonistan- the fulfillment of an ancient desire to unify all Pashtuns on both sides of the Durand line.