I use a company called A.S. Tees quite often in my shop. They make a really nice product. Most of their stuff is made in USA, including a super nice organic cotton shirt for the cheapest price I've found. They have a big ladies' selection, which runs small like AA.
The one big problem is that they don't have a great basic men's t-shirt option that's made in USA. But their import line is superb! The fit is quite comparable to AA, and the fabric is slinkier. The black is blacker too, if that makes sense. And the price is quite nice. Right on par with AA 980 or Gildan SoftStyle. They offer a bunch of colors, but I'm not sure if they have all the same ones. They're made in Haiti, so that means you're helping to rebuild a shattered nation with every purchase. ;)
Anyway, if anyone on Woot staff reads this, check them out! A lot of their business is custom relabeling, so it seems like a perfect match to me.