Ben,
The FAA's rules concerning issuing a Class 1,2 or 3 medical certificate have this to say about 'colour blindness'........
§ 67.103 Eye.
Eye standards for a first-class airman medical certificate are:
(c) Ability to perceive those colors necessary for the safe performance of airman duties
Now it is possible you still may be able to gain a class 1 (ATP) or class 2 (CPL) medical certificate, so I recommend you take a look at
http://www.faa.gov/avr/afs/infoforpi...ners/index.htm and maybe write off to the FAA to ask them.
The reason I say this is becasue I know someone who was colour blind, but still got issued a medical certificate. It involved the tower shining lights at him and as long as he could tell the meaning of the lights, a certificate was issued.
Good luck...
EA