If you already have an air compressor, you can get a small HVLP detail gun from Harbor right now for $20!
http://www.harborfreight.com/cpi/cta...324&pricetype=
I used it for painting my modified 4 * 40 (automotive poly paints). You will get a far better finish than with rollers and brush.
I used latex for my TF Spitfire. I really like the way it came out. I did it before I had the fore-mentioned gun and did it entirely with a Testors Aztec airbrush (about $100) and clear-coated it with rattle can satin waterbase Varithane Diamond polyurethane. I see Harbor has some airbrushes but I cannot comment on their quality.
Scott