MacPherson Leather
A Seattle based leather supply store.

Plastic Lamellar
Premade plastic lamellar plates in a variety of colors. The price is rather reasonable and they look pretty good.

Tandy Leather
Great selection of leathers and leather supplies for all of your crafting needs.

The Ring Lord
Buy precut chainmail rings in a variety of metals. Talk to Shane and Ryan, they can get you a discount, and would also be happy to make you that spiffy armor for a reasonable fee.