I believe I bought these from Dealextreme, but I wouldn't recommend them because it can take over a month to arrive!
Ebay is probably a much better bet. I'd definitely recommend a high CRI version, because the cool white versions can be a little harsh looking.
The resistors were from Radio Shack. I only used two of them because I didn't happen to have one of the correct value. The 10w rating of each resistor is uneccesarily high, but does mean that they run very cool