I agree it is a long shot. But one the top Taliban leaders, Dadullah (not the one captured - - Obeidullah) just claimed this week on British TV to be in direct contact with UBL's "comrades". And he also indicated they would know "easily" if he was "martyred". So, in addition to capturing the highest level Taliban official since 9/11, another high-level Taliban official also claimed this week to have constant, though indirect knowledge of UBL's location/status (by easily knowing whether he were dead or alive).
http://news.bostonherald.com/international/europe/view.bg?articleid=185774
And unless he starts staying in the same hut/cave for more than a couple days, by definition it would have to be a fast turnaround. But again, you are right that it is a long shot. And you know it is exactly like chasing someone up and down the Rocky Mountains from New Mexico to Montana when it was still the "wild West" - - no infrastructure, no highways, and not yet under federal military control. That is almost precisely how long the border is. And the mountains are just as high, and in some cases, higher.
It took 8-9 months in 2003 to find Saddam in a flat, desert country with 150,000+ pairs of "boots on the ground". We've never had more than we have now in Afghanistan (roughly 25,000 total coalition) and only a fraction can be deployed on the border because all the rest are needed to keep the country together (which is bigger than Iraq yet only has a fraction of the coalition forces). This is what was bound to happen when we as a nation, over two decades, and still today, refuse to address a slowly imploding military force structure (especially ground troops who are the only ones who can hold and own real estate). The cupboard is now bare. For the first time since the Reagan administration, we are finally talking about building back a little bit of the the ground forces (90,000 troops) over the next several years. But it is like trying to turn the Titanic around when you see the iceburg in front of you.
I hope they catch him one day. But he is not our most dangerous problem at the moment.