Oh god, yes... I have dim memories of using one of these marker pen based airbrushes, years and years ago. It wasn't Gundam, but some "pro" graphic designer range, possibly Pantone. I don't remember it being much good.
I've got a couple of airbrushes, but I don't really think airbrushing the silver on would be the answer. I think that would result in an uneven finish (if the aim was to use the airbrush to get a "thinner" covering of colour).
But I've spent most of my lunchtime looking at more metallic marker pen options online - I'm going to order a bunch of different brands and try them out - see how the colours compare.
