With spraying you are also not limited to just spray cans and the colors they have available.
Preval sells a disposable sprayer that you can use any latex paint in and it goes on much smoother than rolling.

They are pretty inexpensive too, the unit comes with the reusable bottle and one power unit for around $4-5 and power units are only a couple of bucks. You can find them at most paint stores like Sherwin Williams. For a black cab, I'd go with just regular spray paint, but this opens up options for any color a person could possible want. They also spray poly very well to add a more protective coating if that's desired.
You could go all out and get a Wagner sprayer too, I have two of them. They're not pro grade, but also don't cost as much either and no compressor is needed...
Just some food for thought.
