So having 4 total (3 others) wouldn't be out of the question if all brought different skills to the table? Thanks for your thoughts, would love to get some other opinions too!
http://ycombinator.com/apply.html
"The ideal company would have two or three founders. We'll consider those with four or five. We're reluctant to accept one-person companies, though we have funded a couple."
If there's a strong justification, there's no reason not to have four cofounders. If it's just because that many people wanted to collaborate, you might want to take a hard look about who is going to commit to contribute what. To go with a common illustration, founding means "you're the pig" (https://secure.wikimedia.org/wikipedia/en/wiki/The_Chicken_a...).