Since there seems to be so much interest in the liquid masking techniques, I'll pick some up and give a good test with photos and everything to share with my LW buddies. They have a 2oz bottle for $7 which could well be worth the risk if it ends up being as good for leather as the online reviews say it is for delicate papers & canvas.
On the airbrushes, keep in mind this guy is a detail model maker so his needs will be far more detailed than most of ours. As he mentions on the lower priced airbrushes, they do so-so on the fine detail but spray wide patterns and solid coverage applications just as well. If all you plan to do is solid color or two-color fades on larger projects like holsters, belts, etc. the HF, Badger and Paasche starter guns are a great way to get started.
Radar - yep, the Badger 200 is a good workhorse airbrush, should work just fine. Just be sure to clean first it if it's been sitting awhile.
Side note - I'm going to have to stay away from Coast Airbrush's website. Looking through their classes they have a airbrushing class with Noah from Noah Fine Art/Disney Vinylmation. That would be awesome (and expensive).