This is my recommendation as well. You can't wear them out - I have an Idaho guide friend with 100 days a year in the field for five years to prove it (and he ain't gentle on gear).Take a look at the Kuiu PRO pants. Knee pads and vents. They run small (one size) in the waist and long in the inseam in my experience, but are very similar to their Attack pants, which are bulletproof. Could fit the bill.