Well, Terra's pants are similar to hakama, but they aren't straight-up traditional hakama like you can buy for martial arts. And yes, they are khaki.
You're probably not going to be able to just go to a martial arts or Asian clothing supplier and buy khaki hakama, or khaki anything that looks like hakama. You're better off having it custom-made, by yourself or by a commissioner if you can't do it yourself. They are really weird pants, I helped someone dissect them once to figure out how they were going to sew them, and they're a weird hakama/jeans hybrid.
Founder and Vice-President, Madison Area Costuming Society, a chapter of the International Costumer's Guild
Strange Land Costuming - www.strangelandcostumes.com