Monk,
I turned 20 in March, and for my birthday my Dad's 74 year old bestfriend/climbing buddy gave me a Ventile jacket. The jacket was made by Bobby Sportswear in good old England in either 1969, or 1970. It's very old, and it works just as well today as it was when it was first made. (That just shows you how damn good at inventing stuff you stiff-assed Brits are.
) Anyway, seeing as it's 35+ year old, it's very faded, has almost a silvery-look to the fabric. I think it looks great. I think that it tells a story with the look of the fabic. It's been to Iran, Afghanistan three times, Peru twice, and even Mt. McKinley in Alaska. My Dad had one just like it, in fact he and all of his climbing friends at the time had the same model of jacket, but Ralph's was the only one that has made it this long. My long-winded point is that if I were you, I wouldn't dye the jacket, I'd leave it as is, as yours no-doubt tells a story as well. It's almost like when one purchases a Zippo lighter. The lighter is mechanically guaranteed for life, the finish is not. Why? "It's like a canvass, every scratch has a story to tell."
Cheers,
A.