I sort of built my skills in unison (had an interest in both programming and design since I was a kid), but my career has tended towards the development side, so I guess you could say that I am a programmer by trade that picked up design on the side. Whether or not I am "kickass" is subjective, but people seem generally happy with my work.

The biggest challenge I find is that people do not take designer programmers seriously. Those who do just enough programming to support their interfaces seem to be respected, but as soon as I dive in writing some low level component in C, as an example, my design skills are immediately discounted, it seems.

Programming is design, in my opinion. The way you structure your code, getting the indents and spacings just right to be pleasing to the eye, are the exact same skills you need when you're shifting pixels in photoshop. Thinking about how the next programmer will interpret the meaning of your code is the same skill you need when thinking about how a user will use your interface. I feel the only thing limiting a programmer from becoming a good designer is practice.