Here's a series of never-before-published Dilbert strips that shows how Dilbert and Dogbert met. The series also introduces a character named Bingo who would have been Dogbert's recurring nemesis. The robot in the strip, Ruebert, made a brief appearance in Dilbert but didn't stick.
The story line was created years ago after some Hollywood people told me that Dogbert needed an arch nemesis in order to become an animated movie or TV show. This was before Dilbert found its niche as a work-oriented comic.
I think you'll agree that it's a good thing I didn't take Dilbert in the direction of these comics. They're a good example of what Bil Keane once called "cartoonist cartoons," meaning that only another cartoonist could like them. If you hate them you're in good company with the other six billion inhabitants of Earth. Either way, I thought you might be interested in seeing where Dilbert might have gone had I not paid attention to reader feedback.