What part of it do you want? The pack and MOLLE components can be purchased through US Cav if you want brand new, or from any of a couple dozen jobbers who are buying them used from the DoD with the retirement of old camouflage patterns.

Either way, I'd probably replace the pack frame with the civilian Outdoor Products Enduroflex (which is very similar and has a better track record) or the Gen4 MOLLE packframe from Eagle (same pattern, MUCH MUCH better built). The origional frame has a bad reputation for snapping when you need to be able to count on it.