Yes, the Army IS working on a new pair of pants to complement the Army Combat Shirt. The idea was to develop a pair of trousers that were designed specifically for combat. In addition to protection from flash and flame another major requirement was built in knee protection.
Produced by Massif, manufacturers of the ACS, the Government design features hard knee pads developed by Crye Precision. They are made from 7.3-ounce, fire-resistant twill and offer a reinforced, stretchable seat. This last feature was added since so many Soldiers have to slide down steep slopes in mountainous regions. Limited User Evaluations (LUE) were completed earlier this year in Georgia and West Virginia. Further tests are scheduled for FY10 in Afghanistan but who knows what will happen now due to the Congressional monkey wrench.
It is very important to note that at this point there is no validated requirement nor a formal program to procure the ACP. The development and evaluations are another case of the folks at PEO-Soldier leaning forward in the foxhole.