Chris,

Sorry I think misunderstood you. I thought you wanted to make your own styles for arranger keyboards, so I thought you should start with drum patterns.

For country, blues, rock, and other popular styles , check out Mark Harrison's books. He teaches comping patterns for piano. Besides teaching the parts themselves he gets deep into the theory behind the parts so that you understand how the parts are constructed which will help you eventually make up your own parts.

Mark Harrison is an excellent teacher. I took one private lesson with him in Los Angeles and if I had the time and money I would've continued to study with him via Skype.

I'm pretty sure he has some sample lessons on YouTube. But be sure to check out some of his books. Good luck!