Not sure about the leg ties but ASAT make a BDU that has everything else.

Edit just copied this from the ASAT web site.

Made of 100% brushed cotton. The BDU’s have double seats and knees, military styling/sizing with covered button pockets, waist adjusters and come in long length with blousible tie bottom legs. These are of the highest quality and will last you for many years of rough service.