I have had the same problems as most of you in this area, I am lucky and fortunate that I have passed a practical test (as I have describes on an earlier page) I got 17 out of 18 and the Australian CASA have issued me a medical with no restrictions. This is after failing the plates and the Ishihara tests. Australia has finally pushed forward into the 20th century
I think that most colourblind pilots are very frustrated because they know that their minor lack of colour vision by no way means that they are a unfit pilot. All I can say is keep getting tested you can take the tests as many times as you want in most cases, and all you have to do is pass it once!!!!!
Good luck