I knew a guy who wrote assembler for an 8bit pc without line breaks - he'd just keep typing to the end of the editor line and then continue. And he wasn't producing junk either, he made some really impressive games for the time. That's probably as close as I've seen to "genius."

That said, I wouldn't have wanted to work with him in a commercial environment. It was a way of thinking/programming I could never wrap my head around.