There is a great website called "The Green Loop" that features only sustainable brands and companies.  All the clothing lines have an environmental focus and tons of selection.  On the site, you can shop by brand or the particular item you're looking for.  I highly recommend it. 

Checkout TurningLife.com they are focused entirely on sustainable clothing, bedding, garden and home decor products. They purchase carbon offsets for 100% of their orders shipped.