I have to toot my own horn here because gemstone beads are a specialty at Rings & Things.
We work directly with cutters in China and India. We carry a variety of shapes and stones, mostly in good quality (very few super quality/expensive) at reasonable prices. Most are on line and in our catalog. At our trunk shows you can find a lot of less common shapes and stones and smaller hanks of one time buys - all for cash and carry so you can hand select your strands.
Other gemstone suppliers I can suggest include Rio Grande, Joseph P. Stachura Co, Earthstone.com, Wondersource in NYC, Phoenix in NYC and Jewelweaver.