They sell complete Luxeon blades, driver kits and various parts. Amber is a more unusual color on these sites, but is available from the manufacturer and from specialist retailers.
Some red and amber Luxeon LEDs have slightly different electrical characteristics from the blue/white/green/cyan, so I think you should check first that your driver and cooling setup supports a red or amber LED. If it is rated for a red LED, then it should also work with amber.
The guys at TCSS are quite helpful and fast to respond. There is a forum on their site also that is quite active with experienced saber builders.