There are some places that sell brown ones.
Ebay is a good resource, as there are lots of kilt related accessories on there. Take that with a grain of salt though, as not all are good quality, but some gems do pop up on there, and there seems to be a good handful of respectable sellers, with good gear.

heritageofscotland-net is a seller on there with them... thay also have a website of the same name.

There was another seller on there that sold them too, but the name escapes me... a search for ghillie brogues, and a little patience should yield some positive results, through ebay, or google.