On artwork, I'd coñsider checking local schools/colleges/etc for a talented airbrush artist. When I was in school we longed for a shot at something like that rather than comming up with something just for the sake of something to be graded.
The airbrush folks at a local trade center did a lot of work for some of my later endevers when I lacked the time or equipment to achieve what I wanted. They worked cheaper on cool stuff... but I'm the tipping type, and the work was always great 
(and formerly being good in graphics too, I can be a pretty hàrdnosed judge)
À good airbrush artist can produce work you would have a hard time distinguishing from an actual photograph ..... and students work cheap, sometimes free + supplies. Talk to teachers, but remember that those that can't excell, can at least teach. Ask to see work.
