and I've looked so this is evidence of absence
Only to the extent that you'd expect to find a connection if you looked, and I expect connections between accounts can be hidden pretty reliably to withstand a causal examination if that's seen as a goal. So very weak evidence (however the coin actually happens to land).
I just noticed that calcsam, who just posted two top posts in the main section of the site, only has the 100 karma that he has, so far, gained from those posts.
I don't object to those posts being there, but how did he do that?
Edit: Question answered; Eliezer mucked around with the karma system to make this possible in this specific case.