It appears that the non-acquisition of the armed T-6 may have been planned to take another step, with a potential combat deployment to Afghanistan.  Apparently, the Congressional Armed Services Committees rejected the funding requests for the project:

For more than a year, the Pentagon has wanted to test propeller-driven planes outfitted with reconnaissance sensors and precision-guided weapons in combat to see if they can improve coordination between ground troops and aircraft.

But, lawmakers have not been receptive.

The dynamic of a budget-constrained government trying to win a war with the “best” equipment for the job is educational to watch.

For its part, the military looks to be considering OV-10s — from the 1960s — for the demonstration.