07-27-2010, 03:08 PM
I've never faded black that drastically, but can mention some techniques which may or may not work, so proceed with caution! 
First, there is the old trick of spraying the model with Dullcote, letting it dry, and then applying alcohol over it. This causes the DullCote to turn blotchy white. Somewhere on the net there is a page showing the technique. Google search on dullcote alcohol fade weathering or such... sorry for not taking the time to do it for you.
The other technique is to take some clear water based varnish and sparingly add tan or antique white to it so you get a translucent white... use that to fade the model.
Definitely try these techniques on some junkers before doing it on the real thing!
A final thought, a total repaint may be the way to go, as you mention.
First, there is the old trick of spraying the model with Dullcote, letting it dry, and then applying alcohol over it. This causes the DullCote to turn blotchy white. Somewhere on the net there is a page showing the technique. Google search on dullcote alcohol fade weathering or such... sorry for not taking the time to do it for you.
The other technique is to take some clear water based varnish and sparingly add tan or antique white to it so you get a translucent white... use that to fade the model.
Definitely try these techniques on some junkers before doing it on the real thing!
A final thought, a total repaint may be the way to go, as you mention.
Three Foot Rule In Effect At All Times