OEM keys break because the stress of turning the key is focussed on the on tiny little screw that holds the two parts together.
The aftermakets usually are designed to correct this.
The colored ones i don't know about.
They are all easy enough to find on eBay.
Getting them cut, however, can prove to be expensive.
If you ask around town, you can usually find someone besides the dealer.
Good luck
http://us.lexusownersclub.com/gallery/LS/P1010001http://us.lexusownersclub.com/gallery/LS/P1010002_001
http://us.lexusownersclub.com/gallery/LS/P1010003