I suppose anything is possible but the better question is if you could create an actual automotive grade paint and do so cost effectively. Probably having a degree in chemistry or chemical engineering would help, a lot. I've seen cars painted with house paint and a roller. Kind of looks like house paint and roller but to each his own.

I've seen and done the roller method years ago. That is typically completed with the oil based rustoleum sold in quarts and limited colors which is more like a single stage paint, it can turn out pretty well with a sprayer and some care. I figure that most of the cost in the automotive paint is paying for the research put in to color matching and the other chunk keeping the EPA happy. That's what i'm assuming anyway. It sure would be a handy skill considering the costs.

I'd suspect that there's a little more to it than just color matching (although consistency is very important) and EPA regs. Think about the conditions that automotive paint needs to endure and frankly modern paint seems to pretty darn good. It's not too often that you see paint peeling from a car...

A body shop paint supply store will mix you the exact base color in any size you want. Clear is two part with one being the hardener. That's available in different grades over the internet because it isn't mixed. You also need urethane thinner. And a compressor and paint gun. Sandpaper, tape and masking paper plus plastic.