That part is good, yes. What I'm worried about is the time and effort it would take to get onto the leader board. There is already a profile linked to every username where people can list their startup urls, blogs, or contact info.
An adjustment to your idea that I'd feel more comfortable about would be having an url field next to your name in comments/submissions. So your comment would look like:
1 point by amichail (mystartup) 3 minutes ago