I'm a great fan of the mini spray cans such as the Tamiya ones and the now discontinued Humbrol range.
They are perfect for a nice finish on a large surface and there is all the convenience that goes with them such as no cleaning out!!
Not the cheapest option but for a one off they are cheaper than investing in an airbrush as long as you can find one the correct colour. It is always worth looking through the automobile manufacturers colours as well although most of them are of course gloss finish. Some of these could even be applied and then painted over with a matt finish but I would do a test piece before committing to the model.